Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Catena  

Among soil erosion processes, the initial stage of splash soil erosion caused by throughfall kinetic energy (TKE) plays a crucial role in soil conservation within forest ecosystems. Throughfall (TF) through the upper canopy structure considerably influences TKE in coniferous plantations. Recent studies have revealed that the under-canopy structure laden with dead branches in unmanaged coniferous plantations reduces the TF; however, its specific impacts on TKE and appropriate sampling strategies remain unexplored. This study used 40 splash cups (4 for free kinetic energy and 36 for TKE) for one event (total: 600 splash cups for 15 events) in an unmanaged 36-year-old Japanese cypress plantation laden with dead branches. Additionally, unstratified and stratified Monte Carlo simulations were used to determine optimal sample sizes for stand-scale TKE estimation. Results demonstrated a strong correlation between TKE (J m−2) and TF (mm) (R2 = 0.98) across all events. The stand-scale unit TKE of 12.5 J m−2 mm−1 was much lower than those in seven previous studies with fewer or no dead branches (range: 16.4 to 28.2, median: 18.8 J m−2 mm−1). The previously developed empirical stand-scale unit TKE model considering under-canopy structure solely exhibited a 1.7-fold overestimation. Among the stand structures, a positive relationship of TKE with the distance between a sampling point and its nearest trunk (Dmin) was observed, which was positively correlated with the lowest dead branch height. This indicated that under-canopy dead branches weakened the TKE, likely by reducing TF and raindrop fall velocity. Stratified Monte-Carlo simulation considering the Dmin related spatial patterns of TKE provided a more efficient approach for capturing variability. To achieve high precision with potential errors of ≤5–10 %, a total sample size of 6–15 was appropriate. Our findings implied that the presence of under-canopy dead branches mitigates the soil erosion risk in unmanaged Japanese cypress plantations.

DOI： 10.1016/j.catena.2024.108181

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ecohydrology  

Restoration of natural secondary forests and afforestation of introduced tree species are major effective measures for revegetation. The semiarid Loess Plateau region, characterised by fragile ecosystems and severe soil erosion, is a key area for ecological restoration and protection in China. To illustrate water use characteristics and adaptation to drought in the main forests in this area, we monitored the xylem sap flow of two typical adjacent forest communities with similar climatic characters, a secondary natural forest dominated by oak (Quercus liaotungensis) and a pure plantation of black locust (Robinia pseudoacacia), during 2011–2019 using Granier-type thermal dissipation probes. Solar radiation (RS), air temperature, relative humidity (RH), precipitation and soil water content (SWC) were measured simultaneously. Throughout the whole study period, the mean diameter at breast height (DBH) and total sapwood area increased by 4.5 cm and 1.10 m2 ha−1, respectively in the oak forest and by 1.0 cm and 0.22 m2 ha−1, respectively in the black locust plantation. The monthly stand transpiration was jointly determined by phenological and meteorological factors. At the annual timescale, transpiration of the oak stand was significantly correlated with potential reference evapotranspiration (ET0) and rainfall in the previous year, whereas a significant positive relationship was detected between stand transpiration and SWC in the black locust stand. The analyses of differences between dry and wet years showed that the oak forest exhibited significantly different parameters in the regression analysis of stand transpiration to vapour pressure deficit (VPD), whereas only one parameter was clearly distinct in the black locust plantation, suggesting that its transpiration status did not fully recover even in wet years. The management of black locust plantations with weakened growth conditions should be adjusted under prolonged drought conditions. In contrast, oak forest can maintain the water balance and stable growth by efficiently controlling stomatal behaviour.

DOI： 10.1002/eco.2523

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Hydrology  

Evapotranspiration is an essential process of ecosystem water consumption and is controlled by meteorological factors and soil water conditions. In this study, evapotranspiration based on soil water budget was investigated with respect to major influencing factors during the growing seasons of 2012–2015 for two adjacent forest communities in the semiarid Loess Plateau region: a natural secondary forest dominated by oak (Quercus liaotungensis) and a plantation of exotic black locust (Robinia pseudoacacia). Based on the combination of precipitation, soil water storage, and evapotranspiration dynamics, four distinct periods were differentiated to explore the evapotranspiration response to the main meteorological factors. The correlation matrixes showed that, in most investigated days, evapotranspiration was limited by soil water storage, while an increase in soil water storage shifted dominance from water-related to energy-related factors. The stepwise regression of ≥5-day dry events in each period had a better fitness when paired with the relationship between the summations of evapotranspiration and dominant factors (R2 > 0.7, p < 0.01 for all) than the stepwise results for daily averages. A receiver operating characteristic (ROC) curve was applied to validate the division and determine thresholds. All divisions were thoroughly validated, and the soil water storage thresholds of the black locust (120.2 mm and 150.7 mm) were higher than those of the oak (105.8 mm and 137.9 mm). Our results suggest that the oak had an adaptive water consumption strategy, while the black locust had a higher sensitivity to soil water insufficiency. The method for determining the threshold of soil water storage to separate the dominant factors of evapotranspiration was validated. The approach may be applied to other semiarid forest communities with distinct evapotranspiration response patterns.

DOI： 10.1016/j.jhydrol.2022.128427

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Forest Research  

Although Chamaecyparis obtusa reduces soil pH and cation levels, limited information is available regarding their alterations after clear-cutting. We examined the soil pH and base cations on the upslopes and downslopes of individual trees and stumps of C. obtusa at two distances (0.5 m and 1.0 m) and three depths (0–5, 5–10, and 10–30 cm) in intact- and cut-tree plots. The soil pH was higher in the cut-tree plot than in the intact-tree plot, indicating the recovery of soil pH after clear-cutting. The recovery was more evident in the surface soils (0–5 cm) of downslope areas (0.5 m) than in other soil depths, which implies that the recovery of soil pH was caused by the lack of H+ supply from stumps after clear-cutting. The results of H+ (in H2O: water-soluble and KCl: exchangeable) suggested a lack of soluble H+ in the cut-tree plot. Soil Ca2+ and Mg2+ levels in the surface soil (0–5 cm) were 1.86-fold and 1.93-fold higher in the cut-tree plot than in the intact-tree plot, respectively, implying that the recovery of divalent cations after clear-cutting was caused by a reduction in cation loss through cation exchange with H+ derived from the stemflow. Collectively, soil pH and divalent cations were recovered after clear-cutting because the stemflow had ceased.

DOI： 10.1080/13416979.2022.2048987

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Scopus

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Forest Ecology and Management  

Forest thinning can significantly affect hydrological processes. However, these effects largely vary with forest types, climate, thinning intensity, and hydrological variables of interest. Understanding these effects and their variations can significantly support thinning treatments' design and selection to ensure desired hydrological benefits. In this global-level review paper, we report the first comprehensive meta-analysis on the effects of thinning on major hydrological processes with an emphasis on rainfall partitioning, soil moisture and evapotranspiration processes. The synthesized and reviewed studies encompass different biophysical conditions (climate and forest ecosystems), silvicultural systems, and time scales (from weeks to decades) across continents. The results showed a significant increase in net precipitation, soil moisture and tree-level water use after thinning (the effect sizes are 1.19, 1.14 and 1.56 relative to the value of the control, respectively), while decreases in stemflow and transpiration (the effect sizes of 0.42 and 0.6 relative to the value of the control, respectively). Thinning intensity of about 50% of the stand density is determined as the threshold at or over which hydrological processes are significantly affected. The duration of thinning effect can be set between 2.6 and 4.3 (throughfall) and 3.1–8.6 years (soil moisture and transpiration), asking for repeated thinning in order to effectively sustain these effects. These global averages can serve as benchmarks for assessment and comparisons, but the effects of thinning depend on local biophysical conditions and thinning treatments. The literature review on the rest of the studied hydrological variables suggests that thinning generally enhance runoff to increase water yield and groundwater recharge. Thinning can also have a positive or limited role in water use efficiency (WUE), but it mitigates the effects of drought through increasing WUE. Moderate adverse effects on water quality can be prevented by adequate forest managements to prevent soil degradation. Nevertheless, more researches at relatively less studied regions are needed to support a more robust analysis of these reviewed hydrological variables. The management implications of the synthesized and reviewed results are suggested and discussed within the context of climate change.

DOI： 10.1016/j.foreco.2022.120324

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Scopus

Authorship：Last author   Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)   Publisher：THE JAPANESE FORESTRY SOCIETY  

<p>[in Japanese]</p>

DOI： 10.11519/jfsc.133.0_517

CiNii Research

Authorship：Corresponding author   Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)   Publisher：THE JAPANESE FORESTRY SOCIETY  

<p>[in Japanese]</p>

DOI： 10.11519/jfsc.133.0_518

CiNii Research

Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)   Publisher：THE JAPANESE FORESTRY SOCIETY  

<p>[in Japanese]</p>

DOI： 10.11519/jfsc.133.0_569

CiNii Research

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Forests  

Interception loss (IL) by the forest canopy removes a substantial quantity of rainwater within forested ecosystems. The large-scale unmanaged Japanese coniferous plantations with high stand density (SD) in Japan raise concerns about an additional increasing IL as a result of a new influential factor of dead branches under canopies. Thus, evaluating the usage of IL estimation models is vital to regulating the water and environment in such coniferous plantations. This study aimed to examine the applicability of the reformulated Gash analytical model (RGAM) to unmanaged coniferous plantations with high SD laden with dead branches. We established two plots (P1 and P2) laden with dead branches under the same SD of 2250 stems ha−1 but with different numbers of dead branches (56 vs. 47 branches per tree) in an unmanaged Japanese coniferous plantation. Results demonstrated that a large difference was found in canopy storage capacity (S) in P1 and P2 (3.94 vs. 3.25 mm), which was influenced by the different number of dead branches; therefore, the IL ratio to gross rainfall differed considerably (32.7% in P1 and 26.7% in P2) regardless of the SD being the same. The difference in S enables the RGAM to reflect the influence of dead branch structures on IL, leading to an acceptable RGAM performance for both P1 and P2 (“fair” IL relative errors: −20.2% vs. −16.1%) in the present study of unmanaged coniferous plantations with high SD laden with dead branches.

DOI： 10.3390/f13050657

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：European Journal of Soil Biology  

Periodic droughts and extreme rainfall are predicted to become more common in the future; therefore, it is important to understand how soil N transformation processes driven by soil microbes respond to rainfall events. Differences in forest type, including those in the predominant mycorrhizal type, can have varying effects on soil N transformation. Therefore, we hypothesised that the response of the N transformation processes to rainfall events would differ between forest types, even those that are adjacently located. In this study, we generated a soil moisture gradient in adjacent dryland black locust (Robinia pseudoacacia, non-ectomycorrhizal [ECM]-type) and oak (Quercus liaotungensis, ECM-type) forests and measured the abundance and community composition of fungi and prokaryotes (including ammonia-oxidisers), extractable N content, and net N transformation rates in the soil. Increasing moisture was found to increase nitrate N content in the black locust forest but not in the oak forest. In the oak forest, the abundance of ECM fungi increased with increasing moisture, subsequently enhancing ECM fungal ammonium N uptake and limiting the N availability for ammonia oxidisers, which may reduce the nitrate N production by ammonia-oxidisers. Increased nitrate N uptake by ECM fungi may also result in low soil nitrate N content. The findings of this study indicate that the responses of the nitrate N dynamics to rainfall events can differ between adjacent forests and that this difference may be attributable to the presence of ECM fungi. Therefore, considering the forest mycorrhizal type is vital for predicating the response of forest N cycling under climate change.

DOI： 10.1016/j.ejsobi.2022.103394

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Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers in Forests and Global Change  

Compared to trees, little is known about the respiratory characteristics of bamboo, especially culm respiration. In this study, we measured the respiration rates of current year, 2, 3, and above 4-year-old Moso bamboo (Phyllostachys pubescens) culms and examined its relation to culm morphology and anatomical structure. Current year culms had substantially higher respiration rates (1.9 ± 0.46 μmol m–2 s–1) compared to older culms (2, 3, and above 4-year-old average: 0.17 ± 0.09 μmol m–2 s–1). Culm wood density increased with age, with the concurrent thickening of parenchyma cell walls in the culm tissue. Nitrogen content in the culm tissue decreased with culm age. Both culm wood density and nitrogen content had significant relationships with culm respiration rate. On the other hand, culm height, wall thickness, and circumference did not affect culm respiration rate. Although bamboo culms did not change in size through the year, anatomical changes in the culm tissue that accompanied the aging of a culm affected the respiration. The culm age would have a significant effect on the evaluation of the respiratory characteristics of the bamboo forest. Our results suggested that young culms required a large amount of respiration to grow “inward” as cell wall thickening and also to maintain the relatively large amount of active tissue.

DOI： 10.3389/ffgc.2022.868732

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.3390/f13050657

Other Link： https://www.mdpi.com/1999-4907/13/5/657

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Agricultural Water Management  

Black locust (Robinia pseudoacacia) is widely planted throughout semiarid and subhumid regions of the Loess Plateau of China. Determining the changes in transpiration of this species in different climatic areas is important for revealing the acclimation mechanism of black locust and developing suitable forest management practices, particularly in the context of global climate change. Here, sap flow and canopy conductance of black locust plantation trees in semiarid (Yan'an) and subhumid (Yongshou) sites were quantified using Granier-type thermal dissipation probes and concurrent environmental observations from 2012 to 2017. Several physiological parameters were measured throughout the growing season. The results showed that sap flow was correlated with phenological factors across seasons within a year. However, interannual changes in sap flow were affected mainly by the reference evapotranspiration (ET0) at the Yongshou site, and jointly by precipitation (P), soil water content, and P/ET0 at the Yan'an site. Sap flow response to meteorological factors showed less discrepancy between pre- and post-rainfall periods at the Yan'an site. Moreover, canopy conductance fluctuated less with a wider range of vapor pressure deficit (VPD) and the slope of canopy resistance as a function of VPD was lower, indicating relatively lower sensitivity of stomatal conductance to environmental factors in Yan'an site. Physiological parameters, except for predawn leaf water potential, were significantly different between the two sites. The results suggested that black locust tended to reduce transpiration, modify leaf morphology, and improve water use efficiency to enhance its adaptability to the dryer site. The species changes stomatal regulation characteristics and general growth rate to acclimatize to distinct water habitats.

DOI： 10.1016/j.agwat.2021.107402

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Scopus

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1080/13416979.2022.2048987

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Nitrogen (Switzerland)  

Increased atmospheric nitrogen (N) deposition, caused by anthropogenic activities, has various effects on forest ecosystems. Some reports have investigated the responses in tree transpiration to N addition, but few studies have measured the short-term response of mature tree transpiration to N fertilization. This study aimed to clarify the short-term transpiration response in 27-year-old deciduous hardwood trees to an increase in N availability. We established two plot types (control and N-fertilized plots) in Quercus crispula plantation stands in Hokkaido, Northern Japan. We measured sap flow density (SFD; cm3 m−2 s−1) using a thermal dissipation method for three months during the growing season. In the N-fertilized plot, we added 50 kg N ha−1 yr−1 of ammonium nitrate (NH4NO3) to the forest floor in the middle of the measurement periods. For daily mean SFD, we did not find a significant difference between the control and the N-fertilized plots. Leaf N contents did not differ between treatments, implying a negligible difference in physiological responses and transpiration rates. The slight difference between treatments could be because the trees had already foliated before applying the N fertilizer to our deciduous hardwood trees. The present results indicate that the potential increase in N deposition during the growing season does not immediately alter tree transpiration.

DOI： 10.3390/nitrogen3010006

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Scopus

Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)   Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

<p>本研究では，常緑の針葉樹林と広葉樹林との間で森林を通過する雨水の溶存有機物（DOM）の質にどのような違いがあるのかを検討することを目的とした。このため，福岡県のスギ林およびマテバシイ林に試験プロットを設け，林外雨，林内雨，土壌水の採水装置を設置し，冬季の降雨イベント後にそれらのサンプルを回収した。本発表では超高感度質量分析法FT-ICR-MSを用いてサンプル間のDOMの分子組成の違いを評価したので，その結果を報告する。</p>

DOI： 10.11520/jshwr.35.0_63

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.3390/f11111227

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1016/j.foreco.2019.117730

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.3390/f10090730

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1080/13416979.2019.1647592

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1002/eco.2097

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1080/13416979.2018.1551116

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1080/13416979.2019.1590967

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1007/s11676-018-0784-5

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.5917/jagh.60.193

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.2480/agrmet.D-17-00019

Other Link： https://doi.org/10.2480/agrmet.D-17-00019

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.15287/afr.2017.938

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1007/s00468-017-1555-1

Other Link： https://doi.org/10.1007/s00468-017-1555-1

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1111/1365-2435.12881

Other Link： https://doi.org/10.1111/1365-2435.12881

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DOI： https://doi.org/10.5109/1854026

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DOI： https://doi.org/10.3390/hydrology4030043

Other Link： https://doi.org/10.3390/hydrology4030043

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1007/s11284-017-1471-2

Other Link： https://doi.org/10.1007/s11284-017-1471-2

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.3390/w9060446

Other Link： https://doi.org/10.3390/w9060446

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.4005/jjfs.99.70

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1002/hyp.11162

Other Link： https://doi.org/10.1002/hyp.11162

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/02626667.2016.1266635

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.4005/jjfs.99.70

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DOI： 10.3390/f7100227

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DOI： 10.1080/02626667.2015.1112904

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/eco.1709

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10310-016-0532-7

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10310-016-0525-6

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/hyp.10780

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.agrformet.2016.01.140

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.agrformet.2015.10.006

Other Link： http://www.sciencedirect.com/science/article/pii/S0168192315007327

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.agrformet.2015.08.257

Other Link： http://www.sciencedirect.com/science/article/pii/S0168192315006929

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/hyp.10465

Other Link： http://onlinelibrary.wiley.com/doi/10.1002/hyp.10465/abstract

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/hyp.10520

Other Link： http://onlinelibrary.wiley.com/doi/10.1002/hyp.10520/abstract

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/hyp.10700

Other Link： http://onlinelibrary.wiley.com/doi/10.1002/hyp.10700/abstract

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/hyp.10482

Other Link： http://onlinelibrary.wiley.com/doi/10.1002/hyp.10482/abstract

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10310-015-0495-0

Other Link： http://link.springer.com/article/10.1007%2Fs10310-015-0495-0

Language：English   Publishing type：Research paper (scientific journal)  

DOI： DOI:10.1080/02626667.2015.1112904

Other Link： http://www.tandfonline.com/doi/abs/10.1080/02626667.2015.1112904

Language：English   Publishing type：Research paper (scientific journal)  

DOI： doi:10.2134/jeq2014.09.0401

Other Link： https://dl.sciencesocieties.org/publications/jeq/abstracts/44/4/1225

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3178/hrl.9.35

Other Link： http://www.hrljournal.org/archives/1758

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/eco.1515

Other Link： http://onlinelibrary.wiley.com/doi/10.1002/eco.1515/abstract

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/1442-1984.12076

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/hyp.10213

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.chemosphere.2014.02.046

Other Link： http://www.sciencedirect.com/science/article/pii/S0045653514002501

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2134/jeq2014.09.0401

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.foreco.2014.08.041

Other Link： https://www.sciencedirect.com/science/article/pii/S0378112714005544

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.agrformet.2014.06.011

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/eco.1428

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/treephys/tpu041

Other Link： http://treephys.oxfordjournals.org/content/early/2014/05/29/treephys.tpu041.short

Language：Japanese   Publishing type：Research paper (scientific journal)  

Observation of canopy interception loss in an oak forest

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jhydrol.2013.09.053

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s11270-013-1763-2

Language：English   Publishing type：Research paper (scientific journal)  

Headwater streams are crucial parts of overall watershed dynamics because they comprise more than 50-80% of stream networks and watershed land areas. This study addressed the influence of headwater areas (ephemeral and intermittent) on stormflow characteristics following harvest within three first-order catchments in the Upper Gulf Coastal Plain of Mississippi. Four treatments including two Best Management Practices (BMPs) were applied: BMP1 - removal of all merchantable stems while leaving understory intact with minimum surface soil disturbance; BMP2 - same as BMPl with the addition of logging debris to the drainage channel; Clearcut - total harvest with no BMPs applied; Reference - left uncut as a control. Following harvesting, the increase in water table depth ranged from 1.6 cm in BMPl to 28.2 cm in the clearcut treatment during 2008, and from 10.5 cm in BMPl to 54.2 cm in BMP2 during 2009. However, impacts of timber harvesting on peak discharge, storm discharge, and time of concentration were not consistent with water table response. Response time to stormflow was reduced significantly in harvested treatments (BMP2 and unrestricted harvest) probably as a result of decreased evapotranspiration and increased soil disturbance.

Language：English   Publishing type：Research paper (scientific journal)  

Recently, large forest fires have occurred along the Baekdu mountain range in the eastern coastal regions of the Republic of Korea. The turbidity of water in streams increased substantially after the forest fires, leading to substantial deterioration in the water quality. Residents living near the burned areas have requested remediation measures to reduce the turbidity in streams during rainfall events. Our research was conducted at the locations affected by the Donghaean fire in 2000 to investigate: 1) the influence of forest fires on the physical properties of the soil and 2) the effectiveness of contour-felled log erosion barriers (CFLEBs) in reducing surface soil erosion. The CFLEBs is a remediation technique in which felled burnt trees are laid along the ground contour to promote water infiltration into the soil and to reduce the movement of sediment by decreasing the amount of surface runoff. The results showed that the bulk density of the surface soils in the burned areas was greater than that in the unburned areas, and that the mesopore ratio of the surface soils in the burned areas was less than that in the unburned areas. These results implied that forest fires damaged the physical structure of the surface soil and made the surface soil more vulnerable to post-fire runoff and hillslope erosion. The slope lysimeter experiments conducted over two years from May 2010 to June 2012 showed that the annual average sediment yields were 17.8 g m^-2 yr^-1 in areas treated with CFLEBs and 133.6 g m^-2 yr ^-1 in areas not treated with CFLEBs. These results demonstrate that CFLEBs are an effective measure for controlling surface soil erosion and thus reducing turbidity in streams. Since burnt trees are often cut down in the Republic of Korea after forest fires to prevent the spread of damage caused by insects epidemics, the construction of CFLEBs from already felled trees would be an economically and ecologically useful method to reduce surface soil erosion and turbidity in streams over large scales.

Language：English   Publishing type：Research paper (scientific journal)  

The potential for soil erosion is strongly affected by land use. A proper modeling approach should be selected to explicitly assess the impacts of land use changes on soil erosion at a river basin scale. The reliability of simulation results from erosion models is circumscribed by considerable spatial variation in many parameters. In this study, a grid-based distributed soil erosion and sediment transport model was used in conjunction with a laboratory rainfall simulation experiment to determine the impact of land use changes on soil erosion and sediment yield in a river basin during individual storms. Land use changes in the Lushi Basin, primarily in Henan, China, were analyzed by comparing the historical land use maps in 1990 and 1995. Through comparing the results for four selected storms that were compiled using these two land use maps, it was found that the average erosion rates increased from 1989 to 1996. The increase in average erosion rates followed the land use changes, especially the transformation of forest to farmland. The results indicated that even slight land use change, from forest to farmland or vice versa, had a significant effect on regional soil erosion rates and sediment supply to rivers.

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

In recent years, Moso bamboo (Phyllostachys pubescens) forests have rapidly expanded in Japan by replacing surrounding coniferous and/or broadleaved forests. To evaluate the change in water yield from forested areas because of this replacement, it is necessary to examine evapotranspiration for Moso bamboo forests. However, canopy interception loss, one of the major components of evapotranspiration in forested areas, has been observed in only two Moso bamboo forests in Japan with relatively high stem density (~7000 stems/ha). There are, in fact, many Moso bamboo forests with much lower stem density. Thus, we made precipitation (Pr), throughfall (Tf) and stemflow (Sf) observations for 1 year in a Moso bamboo forest with stem density of 3611 stems/ha and quantified canopy interception loss (Ic). Pr and Ic for the experimental period were 1636 and 166 mm, respectively, and Ic/Pr was 10%. The value was approximately the same as values for the other two Moso bamboo forests and lower than values for coniferous and broadleaved forests. On the other hand, Tf/Pr and Sf/Pr for our forest (86% and 4%, respectively) were approximately 10% of Pr larger and smaller than values for the other two Moso bamboo forests. These results suggest that the difference in stem density greatly affects precipitation partitioning (i.e. Tf/Pr and Sf/Pr) but does not greatly change Ic/Pr.

DOI： 10.1002/hyp.9359

Language：English   Publishing type：Research paper (scientific journal)  

To clarify characteristics of carbon (C) allocation in a Bornean tropical rainforest without dry seasons, gross primary production (GPP) and C allocation, i.e., above-ground net primary production (ANPP), aboveground plant respiration (APR), and total below-ground carbon flux (TBCF) for the forest were examined and compared with those from Amazonian tropical rainforests with dry seasons. GPP (30.61 MgC ha^-1 year^-1, eddy covariance measurements; 34.40 MgC ha^-1 year^-1, biometric measurements) was comparable to those for Amazonian rainforests. ANPP (6.76 MgC ha^-1 year^-1) was comparable to, and APR (8.01 MgC ha^-1 year^-1) was slightly lower than, their respective values for Amazonian rainforests, even though aboveground biomass was greater at our site. TBCF (19.63 MgC ha^-1 year^-1) was higher than those for Amazonian forests. The comparable ANPP and higher TBCF were unexpected, since higher water availability would suggest less fine root competition for water, giving higher ANPP and lower TBCF to GPP. Low nutrient availability may explain the comparable ANPP and higher TBCF. These data show that there are variations in C allocation patterns among mature tropical rainforests, and the variations cannot be explained solely by differences in soil water availability.

DOI： 10.1007/s10265-012-0544-0

Language：English  

DOI： 10.1093/treephys/tpt029

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Recently, securing water resources has become one of the major purposes of forest management in Japan; this is done by thinning in coniferous plantations, replacing coniferous plantations with broadleaved forests, and conducting clearing or thinning operations in bamboo forests to reduce water loss to evapotranspiration. However, the effects of forest management practices on water resources have not been fully clarified because of a lack of evapotranspiration data from Japanese forests. Transpiration is a primary component of evapotranspiration in forested areas. We presented an overview of transpiration measurements based on the sap flow technique, a typical method used for measuring transpiration, to contribute to the accumulation of transpiration data for Japanese forests. Firstly, we compared the sap flow technique with other transpiration measurement methods and showed the usefulness of the sap flow technique for examining the effect of forest management practices on transpiration. Secondly, we explained the scaling-up procedures needed to up-scale from measures of sap flux densities to individual tree-scale transpiration and from individual tree-scale transpiration to stand-scale transpiration. Finally, we summarized stand-scale transpiration measurements based on the sap flow techniques as used in Japan, and recommend the types of forests which should be measured to help land and water managers have an informed discussion related to modifying forest management with the goal of securing water resources by forest practices. Measurements of transpiration are needed from larch plantations, broadleaved forests, and bamboo forests in Japan. Transpiration data measured in Japanese cedar and Japanese cypress plantations at ages of more than 60 years and less than 20 years would also be useful for the discussion.

Language：English   Publishing type：Research paper (scientific journal)  

Nitrogenous air pollutants including nitrogen dioxide (NO ₂), nitric acid (HNO ₃), nitrate (NO _{3 -}), ammonia (NH ₃), ammonium (NH ₄ +), and nitrous acid (HONO) were characterized at an urban forested (UF) site in Hiroshima and at a suburban forested (SF) site in Fukuoka, western Japan, using an annular denuder system for 1 year from May 2006 to May 2007 to compare the concentrations and chemical species of atmospheric nitrogenous pollutants between UF and SF sites. The proximity of the urban area was reflected in higher NO ₂ concentrations at the UF site than at the SF site. NO ₂ was more oxidized at the SF site because it is farther from an urban area than the UF site, which was reflected in higher concentrations of HNO ₃ at the SF site than the UF site. HNO ₃ and acidic sulfate is neutralized by NH ₃, existing as ammonium nitrate (NH ₄NO ₃) and ammonium sulfate [(NH ₄) ₂SO ₄] at the UF site. At the SF site, acidic sulfate is neutralized by NH ₃, existing as (NH ₄) ₂SO ₄, but NH4NO3, had scarcely formed at the SF site. A much higher HONO concentration was observed at the UF site than at the SF site, especially in winter and spring at night, which could be explained by higher NO ₂ concentrations at the UF site because of its proximity to an urban area and stagnant meteorological conditions. Atmospheric HONO determination was critical in evaluating the possibility of damage to trees in UF areas.

DOI： 10.1007/s11270-012-1294-2

Language：English   Publishing type：Research paper (scientific journal)  

T'his study sought to determine the lowest number of storm events required for adequate estimation of annual nutrient loads from a forested watershed using the regression equation between cumulative load (ΣL) and cumulative stream discharge (ΣQ). Hydrological surveys were conducted for 4 years, and stream water was sampled sequentially at 15-60-min intervals during 24 h in 20 events, as well as weekly in a small forested watershed. The bootstrap sampling technique was used to determine the regression (ΣL-ΣQ) equations of dissolved nitrogen (DN) and phosphorus (DP), particulate nitrogen (PN) and phosphorus (PP), dissolved inorganic nitrogen (DIN), and suspended solid (SS) for each dataset of ΣL and ΣQ. For dissolved nutrients (DN, DP, DIN), the coefficient of variance (CV) in 100 replicates of 4-year average annual load estimates was below 20% with datasets composed of five storm events. For particulate nutrients (PN, PP, SS), the CV exceeded 20%, even with datasets composed of more than ten storm events. The differences in the number of storm events required for precise load estimates between dissolved and particulate nutrients were attributed to the goodness of fit of the ΣL-ΣQ equations. Bootstrap simulation based on flow-stratified sampling resulted in fewer storm events than the simulation based on random sampling and showed that only three storm events were required to give a CV below 20% for dissolved nutrients. These results indicate that a sampling design considering discharge levels reduces the frequency of laborious chemical analyses of water samples required throughout the year.

DOI： 10.1007/s10661-011-2299-9

Language：English  

DOI： 10.1002/hyp.9195

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.3178/jjshwr.24.261

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

In western Japan, Moso bamboo (Phyllostachys pubescens) forests have been expanding by replacing surrounding forests (e.g., coniferous plantation forests), which raises concerns about possible changes in terrestrial water and carbon cycles. Canopy conductance (G _c) is a critical parameter for determining canopy transpiration and photosynthesis. To clarify the characteristics of G _c for Moso bamboo forests, we calculated G _c during a growing season for a Moso bamboo forest on the basis of canopy transpiration measurements made using the sap-flux method, and then compared the G _c value with values for coniferous plantation forests in western Japan. G _c was primarily related to the vapor pressure deficit and secondarily to solar radiation, similar to the results obtained for other temperate forests. Under light-saturated conditions, G _c for the bamboo forest was approximately twice that for the coniferous plantation forests despite the lower leaf area index for the bamboo forest. This implies higher canopy transpiration and photosynthesis for the bamboo forest, and therefore possible changes in terrestrial water and carbon cycles due to the replacement of coniferous plantation forests by bamboo forests.

DOI： 10.1016/j.agrformet.2012.01.004

Language：English   Publishing type：Research paper (scientific journal)  

In this study, we aimed to clarify spatial variations in xylem sap flow, and to determine the impacts of these variations on stand-scale transpiration (E) estimates. We examined circumferential and radial variations in sap flow velocity (F _d) measured at several directions and depths in tree trunks of black locust (Robinia pseudoacacia) and native oak (Quercus liaotungensis), both of which have ring-porous wood anatomy, in forest stands on the Loess Plateau, China. We evaluated the impacts of circumferential variations in F _d on stand-scale transpiration estimates using a simple scaling exercise. We found significant circumferential variations in F _d in the outermost xylem in both species (coefficients of variation = 20-45%). For both species, F _d measured at the inner xylem was smaller than that of the outermost xylem and the F _d at the depth of > 10 mm was almost zero. The simple exercises showed that omitting circumferential variations in F _d affected the E estimate by 16-21%, which was less than the effects of omitting within-tree radial and tree-to-tree variations in F _d in both species. These results suggest that circumferential variations in F _d can be a minor source of error for E estimates compared with within-tree radial and tree-to-tree variations in F _d, regardless of the significant circumferential variations.

DOI： 10.1002/hyp.8205

Language：English   Publishing type：Research paper (scientific journal)  

Based on three-year remote sensing data and cellular automata (CA)-Markov model, this study analyzed the temporal and spatial variation features of land use and land cover change in Hulun Lake Nature Reserve from 1999 to 2007. The result indicated that during the period between 1999 and 2007, there had been relatively great changes in land use type in Hulun Lake Nature Reserve, with ecological problems such as grassland degradation and water area shrinkage, becoming increasingly serious. Via analyzing the area variations of various land use types and the historical statistics of Hulun Lake's water level during this period, the study found that the water use of the upstream by the population pressure and economy development might be related with the decline in Hulun Lake's water levels which caused the increase in the sandy area. This kind of information is necessary for the land management of the area and will help in the ecosystem conservation in future.

Language：English   Publishing type：Research paper (scientific journal)  

Annual forest evapotranspiration (ET) is highly variable among various sites. Zhang's model (Zhang et al., 2001) has been widely used for predicting the spatial variation in ET. The forest component of the model employs limiting theory and assumes constant annual potential evaporation (E ₀=1410mm) by regressing data recorded at 56 forest sites. However, most of the data used in determining E ₀ were recorded for limited regions (Australia, African countries, and the United States). We summarized 829 forest ET data items obtained for sites around the world from earlier publications. Using the dataset, we showed that Zhang's model overestimates forest ET in temperate and boreal regions with low annual mean temperature (T) owing to the E ₀ value. We revised the E ₀ term of Zhang's model so as to consider the dependency of E ₀ on T using the dataset. The revised model did not overestimate forest ET in temperate and boreal regions. Consequently, we recommend revising the E ₀ term of Zhang's model when predicting forest ET in these regions.

DOI： 10.1016/j.jhydrol.2011.12.030

Language：English   Publishing type：Research paper (scientific journal)  

The sensitivity of land surface energy partitioning to near-surface air temperature (T_a) is a critical issue to understand the interaction between land surface and climatic system. Thus, studies with in situ observed data compiled from various climates and ecosystems are required. The relations derived from such empirical analyses are useful for developing accurate estimation methods of energy partitioning. In this study, the effect of T_a on land surface energy partitioning is evaluated by using flux measurement data compiled from a global network of eddy covariance tower sites (FLUXNET). According to the analysis of 25 FLUXNET sites (60 site-years) data, the Bowen ratio is found to have a linear relation with the bulk surface resistance normalized by aerodynamic and climatological resistance parameters in general, of which the slope and intercept are dependent on T_a. Energy partitioning in warmer atmosphere is less sensitive to changes in land surface conditions. In addition, a negative relation is found between Bowen ratio and T_a, and this relation is stronger above less vegetated surface and under low vapor pressure deficit and low received radiative energy condition. The empirical results obtained in this study are expected to be useful in gaining better understanding of alternating surface energy partitioning under increasing T_a.

DOI： 10.1007/s00704-011-0520-y

Language：English   Publishing type：Research paper (scientific journal)  

To examine the feasibility of using ecophysiological data from excised leaves for a meteorological simulation model of gas exchange, we compared the obtained gas exchange rates and the modelled ones using excised leaves and those using intact leaves. Instantaneous gas exchange rates of excised leaves and stomatal control in response to environmental conditions were not significantly different from those of attached leaves. Modelled gas exchange rates based on excised leaf data showed a good fit to the diurnal patterns of in situ measurements. This suggests that use of excised leaf data to predict gas exchange of intact leaves is permissible as long as the effects of excision are pre-screened as described in this paper.

DOI： 10.1002/hyp.8107

Language：English   Publishing type：Research paper (scientific journal)  

The prevalence of forestry practices such as thinning and pruning have gradually decreased since the 1980s. Researchers have noted an increased flood risk with decreased forestry practices for coniferous plantations in Japan on the basis of infiltration and overland flow measurements at a plot scale (typically several square meters). However, no studies have examined changes in peak flow with decreased forestry practices at a watershed scale (typically several tens or hundreds of square kilometers) even though flood disasters generally occur at this scale in Japan. We examined changes in frequency distributions of daily precipitation (P) and runoff (Q) during the period 1979-2007 at the Terauchi watershed, where forestry practices are known to have decreased. For this purpose, we divided P and Q data into 14 and 15 classes according to the magnitude, respectively, and examined changes in the frequency for each class during the period. We observed no significant increasing trend for any P or Q class. Even when taking into account the effect of interannual variations in precipitation on the frequency for each Q class, there was no significant increasing trend in the frequencies except for two Q classes with moderate Q values. These results suggest that the increase in flood risk due to decreased forestry practices might be less than expected.

DOI： 10.1016/j.jenvman.2011.01.010

Language：English   Publishing type：Research paper (scientific journal)  

In pine wilt disease (PWD), embolized tracheids arise after virulent pine wood nematodes (PWN), Bursaphelenchus xylophilus, invade the resin canal of pine tree; infected pine trees finally die from significant loss of xylem water conduction. We used a compact magnetic resonance imaging system with a U-shaped radio frequency (rf) probe coil to reveal the developmental process of the xylem dysfunction in PWD. Multiple cross-sectional slices along the stem axis were acquired to periodically monitor the total water distribution in each 1-year-old main stem of two 3-year-old Japanese black pines (Pinus thunbergii) after inoculation of PWN. During the development of PWD, a mass of embolized tracheids around the inoculation site rapidly enlarged in all directions. This phenomenon occurred before the significant decrease of water potential. Some patch-like embolisms were observed at all monitoring positions during the experimental period. Patchy embolisms in a cross-section did not expand, but the number of patches increased as time passed. When the significant decrease of water potential occurred, the xylem dysfunctional rate near the inoculation point exceeded 70%. Finally, almost the whole area of xylem was abruptly embolized in all cross-sections along the stem. This phenomenon occurred just after water conduction was mostly blocked in one of the cross-sections. Thus, it appears that the simultaneous expansion of embolized conduit clusters may be required to induce a large-scale embolism across the functional xylem. Consequently, xylem dysfunction in infected trees may be closely related to both the distribution and the number of PWN in the pine stem.

DOI： 10.1104/pp.110.170282

Language：English   Publishing type：Research paper (scientific journal)  

Other Link： http://onlinelibrary.wiley.com/doi/10.1002/hyp.8107/abstract

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.ecolmodel.2011.01.021

Other Link： http://www.sciencedirect.com/science/article/pii/S0304380011000536

Language：English   Publishing type：Research paper (scientific journal)  

The papers in this issue are a selection of the presentations made at the second International Conference on Forests and Water in a Changing Environment. This special issue 'Forest Ecohydrological Processes in a Changing Environment' covers the topics regarding the effects of forest, land use and climate changes on ecohydrological processes across forest stand, watershed and regional spatial scales.

DOI： 10.1002/eco.218

Language：English   Publishing type：Research paper (scientific journal)  

Modern ecohydrologic science will be critical for providing the best information to policy makers and society to address water resource challenges in the 21st century. Implicitly, ecohydrology involves understanding both the functional interactions among vegetation, soils, and hydrologic processes at multiple scales and the linkages among upland, riparian, and aquatic components. In this paper, we review historical and contemporary ecohydrologic science, focusing on watershed structure and function and the threats to watershed structure and function. Climate change, land use change, and invasive species are among the most critical contemporary issues that affect water quantity and quality, and a mechanistic understanding of watershed ecosystem structure and function is required to understand their impacts on water quantity and quality. Economic and social values of ecosystem services such as water supply from forested watersheds must be quantified in future research, as land use decisions that impact ecohydrologic function are driven by the interplay among economic, social, political, and biological constraints. Future forest ecohydrological research should focus on: (1) understanding watershed responses to climate change and variability, (2) understanding watershed responses to losses of native species or additions of non-native species, (3) developing integrated models that capitalize on long-term data, (4) linking ecohydrologic processes across scales, and (5) managing forested watersheds to adapt to climate change. We stress that this new ecohydrology research must also be integrated with socio-economic disciplines. Published in 2011. This article is a US Government work and is in the public domain in the USA. This article is a US Government work and is in the public domain in the USA. Published in 2011 by John Wiley & Sons, Ltd.

DOI： 10.1002/eco.193

Language：English   Publishing type：Research paper (scientific journal)  

The spatially and temporally variable characteristics of soil infiltration process are a major physical constraint for the irrigated lands to achieve higher irrigation efficiencies. Substantial works have been directed towards developing state-dependent models to estimate the infiltration characteristics of soils, which are not suitable for continuous simulation of the infiltration process under complex rainfall or irrigation intensities. In this study, the time compression approximation (TCA) method is coupled with the Philip's infiltration equation, and the coupled infiltration model is extended beyond the ponding time to estimate the postponding infiltration process. An offset time is then introduced into the coupled infiltration model for solving the problems caused by the necessities of refreshing the state-dependent variables stepwisely. This simplifies the determination processes of the model's variables and amplifies its applicability under complex rainfall or irrigation intensities. By using the soil expA(c)rimental data, the TCA based infiltration model shows good performance in predicting the cumulative infiltration. The deviation coefficients of the infiltration predictions range from 0.59% to 34.74%, and the Nash coefficient of efficiency is calculated to be 82% for all the simulated results. This suggests that the proposed TCA based infiltration model could be suitable for the management of sprinkler irrigation.

Language：English   Publishing type：Research paper (scientific journal)  

Water shortage for agricultural water use is a major problem m the Yellow River basin. I his research use NDVI value, meteorological data, supervised classification in remote sensing image and actual statistical data to estimate and verify the wheat and maize distribution and the relevant crop water productivity values in the Yellow River basin. The validation of the method is performed by comparing the results with the distribution of CIESIN statistic data for 1990. To obtain the accurate crop water productivity, the study used and compared two methods for calculating the total crop water productivity. The first one is to sum the crop water productivity calculated by multiplying the crop water requirement per unit area and the estimated planting total area of crops in the basin. The second one is to sum the crop water productivity calculated for each province. The research found that the remote sensing data could efficiently improve the accuracy in estimating the crop water productivity.

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/hyp.7898

Language：English   Publishing type：Research paper (scientific journal)  

Sap flow techniques are practical tools for estimating tree transpiration. Though many previous studies using sap flow techniques did not consider azimuthal variations of sap flux density (F_d) on xylem trunk to estimate tree transpiration, a few studies reported that ignoring the azimuthal variations in F_d could cause large errors in tree transpiration estimates for some tree species. Therefore, examining azimuthal variations in F_d for major plantation tree species is critical for estimating tree transpiration. Using the thermal dissipation method, we examined azimuthal variations in F_d in six trees of Japanese cypress Chamaecyparis obtusa (Sieb. et Zucc.) Endl., which is one of the most common plantation tree species in Japan. We recorded considerable variations among F_d at four different azimuthal directions. The F_d value for one aspect was more than 100% larger than those for the other aspects. We calculated differences between tree transpiration estimates based on F_d for one to three azimuthal directions and those based on F_d for four aspects. The differences relative to tree transpiration estimates based on F_d for four aspects were typically 30, 20, and 10% in accordance with the F_d for one, two, and three measurement aspects, respectively. This finding indicates that ignoring azimuthal variations could cause large errors in tree transpiration estimates for Japanese cypress.

DOI： 10.1007/s10310-010-0202-0

Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The applicability of sap flux (F_d) measurements to bamboo forests has not been studied. This study was undertaken to establish an optimal and effective design for stand-scale transpiration (E) estimates in a Moso bamboo forest. To this aim, we validated F_d measurements in Moso bamboos in a cut bamboo experiment. In addition, we analyzed how sample sizes affect the reliability of E estimates calculated from F_d and conducting culm area (A_{S_b}). In the cut bamboo experiments, we found that F_d measurement using a 10mm probe was a valid means of determining the water-use behavior of a Moso bamboo, although a specific correction was needed. Furthermore, we calculated E from stand A_{S_b} (A_{S_stand}) and mean stand F_d (J_S). Employing Monte Carlo analysis, we examined potential errors associated with sample size in E, A_{S_stand}, and J_S using an original dataset with A_{S_b} and F_d measured for 40 and 16 individuals, respectively. Consequently, we determined the optimal sample size for both A_{S_stand} and J_S estimates as 11. The optimal sample sizes for J_S were almost the same under different vapor pressure deficit and soil moisture conditions. The optimal sample size for J_S at the study site was less than that of a coniferous plantation in the same region probably owing to small individual-to-individual variations in sap flux in the Moso bamboo forest. Our study concludes that sap flux measurements are an applicable technique for assessing water use in Moso bamboo forests.

DOI： 10.1016/j.foreco.2010.07.012

Language：English   Publishing type：Research paper (scientific journal)  

In western Japan, Moso bamboo (Phyllostachys pubescens) forests have been expanding by replacing surrounding vegetation such as coniferous plantation forests and natural broadleaved forests. It has been speculated that the replacement of surrounding vegetation by bamboo forests could alter the vegetation water cycle and available water resources. We quantified stand-scale transpiration (E) in a bamboo forest on the basis of sap-flux measurements and compared the E value with values for coniferous forests. The annual E was estimated to be 567 mm. Seasonal trends in E primarily corresponded to seasonal trends in the vapor pressure deficit. Annual E for the bamboo forest was higher than that for the coniferous forests by 12% of annual precipitation (P). This difference in annual E is comparable with the difference in annual interception evaporation (I) relative to P between bamboo and coniferous forests; previous studies reported lower I for bamboo forests by ∼10% of P. Thus, the sum of E and I was comparable for bamboo and coniferous forests. As this study is the first measuring E of bamboo forests, further studies are required to examine the generality of our results.

DOI： 10.1016/j.foreco.2010.06.040

Language：English   Publishing type：Research paper (scientific journal)  

To investigate the impacts of the invasion by bamboo on fluxes of nutrients and pollutants, the nutrient/pollutant fluxes and canopy interactions, including neutralization of acidity, leaching and uptake of nitrogen (N), were characterized in conjunction with rainfall partitioning in a Moso-bamboo (Phyllostachys pubescens) forest. Measurements of precipitation volume, pH, major ions, and silicate (SiO₂) in rainfall, throughfall and stemflow were collected weekly in a Moso-bamboo forest located in Munakata City, Western Japan for 1 year. Results showed that rainfall partitioning into stemflow was larger than that for other types of forest, which may be due to the properties of Moso-bamboo forest structure, such as a straight and smooth culm. Inorganic N (NO₃^- + NH₄⁺) and S (SO₄^2-) fluxes of throughfall and stemflow were approximately 1.6 and 1.3 times higher than that of rainfall, respectively. Contribution of stemflow flux to inorganic N and S fluxes to the forest floor was high. This could be due to lower uptake of inorganic N through culm and a higher rainfall partitioning into stemflow than that for other types of forest. The Moso-bamboo canopy neutralized rainfall acidity, reducing the fluxes of potentially acidifying compounds via throughfall and stemflow. Canopy leaching of K⁺ was distinctly higher than that of Mg²⁺ and Ca²⁺ and could be related to the high mobility of K⁺ in plant tissues. Cl^- and SiO₂ were readily leached as for K⁺. The impact of the invasion by bamboo on nutrient cycling was discussed.

DOI： 10.1002/hyp.7706

Language：English   Publishing type：Research paper (scientific journal)  

The growth of tropical rainforest in Amazon is critically vulnerable to the change in rainfall and radiation than in temperature, and that amount of rainfall and cloudiness in the northeast region of South American is strongly affected by the Atlantic sea surface temperature (SST). Results from recent model experiments for future climate projection have indicated a reduction of Amazonian greenness by a weakening of tropical vapor circulation system related with the change in SST. Therefore, the observational investigation of the relations between the Amazon greenness and Atlantic SST is fundamental to understand the response of Amazonian tropical forest to climate change. In this study, the effect of Atlantic SST on the spatial and temporal change of the Normalized Difference Vegetation Index (NDVI) in the Amazonian region is examined by using satellite remote sensing data for the period of 1981-2001. A strong correlation between NDVI and SST is found for certain regions in Amazon during the periods of 1980s and 1990s, respectively. In addition, strong correlations with NDVI lagging behind SST for two months and one year, respectively, are also identified from the interannual December-to-February (rain season) variations during 1981-2001. Despite these findings, the mechanisms behind the identified correlation remain unclear. Further analyses using observed precipitation and radiation data are required to understand the potential changes of Amazonian rainforest in the context of global warming.

DOI： 10.1016/j.ecoinf.2010.05.005

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Japan developed large areas of coniferous plantations for timber production between the 1950s and 1970s; however, forestry practices such as thinning, pruning, and harvesting in most of the plantations have declined since the 1980s. Researchers speculated that reduced forestry practices could reduce run-off and therefore available water resources. As a countermeasure to this potential risk, many local governments have introduced local taxes to stimulate forestry practices in the plantations. However, no studies have presented evidence for decreased annual run-off and/or low flow in watersheds where forestry practices have declined. As a starting point for assessing this risk, this study examined potential changes in the annual run-off and low flow in the Terauchi watershed. A large area of this watershed was covered with coniferous plantations. We first surveyed the annual investment in forestry operations and the number of forest owners in the city of Amagi. (Note that Amagi includes the Terauchi watershed.) Both decreased during the period 1979-2007, indicating reduced forestry practices. The frequency distribution of plantation tree ages in the watershed also suggested reduced forestry practices. After excluding the effect of precipitation, we examined potential changes in the annual run-off and low flow during the period 1979-2007. We did not observe significant decreases in the annual run-off and low flow during the period. Thus, the risk of decreased water resources might be less than expected, and countermeasures to the risk should be reconsidered.

DOI： 10.1002/hyp.7657

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10310-010-0184-y

Other Link： https://www.tandfonline.com/doi/full/10.1007/s10310-010-0184-y

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/hyp.7620

Language：English   Publishing type：Research paper (scientific journal)  

A dye injection method was used to elucidate the xylem water-conducting pathways of 34 broadleaved evergreen trees growing in southern Japan: two semi-ring-porous, 26 diffuse-porous, five radial-porous and one non-vessel species. The large earlywood vessels in semi-ring-porous species have a water transport function in only the outermost annual ring, as in deciduous ring-porous species. On the other hand, the small vessels in semi-ring-porous species maintain the water transport function in many outer annual rings. For the other xylem-type species, the many vessels in many outer annual rings have a water transport function. In diffuse-porous species, we categorized the water-conducting pattern within the annual rings into two types: d1 type, where water travels through vessels in the whole region; and d2 type, where water travels mainly through the earlywood vessels. The pattern in radial-porous species is similar to that in the d1 type; the pattern in non-vessels species is similar to that in the d2 type. The vessel diameter in radial-porous species is similar to that of the earlywood vessels of semi-ring-porous species. These results suggest that the conduit diameter size is only one of many factors determining the water-conducting pathways of broadleaved evergreen species.

DOI： 10.1007/s00468-010-0428-7

Language：English   Publishing type：Research paper (scientific journal)  

Temperature data in the mountain forest regions are often extrapolated from temperature data recorded at base stations at lower elevation. Such extrapolation is often based on elevation differences between target regions and base stations at low elevation assuming a constant temperature lapse rate throughout the year. However, this assumption might be problematic where slope circulation is active and decoupled from the regional circulation. To model the seasonal change in the lapse rate, the authors compared daily maximum (T_max) and minimum temperatures (T_min) observed at a mountain forest site (Kog-Ma; 1300-m altitude) with those observed at the bottom of the basin (Chiang-Mai; 314-m altitude) in northern Thailand, where slope circulation is active and decoupled from the regional circulation. The difference in T_max between Kog-Ma and Chiang-Mai (ΔT_max; Kog-Ma minus Chiang-Mai) was relatively unchanged throughout the year. However, the difference in T_min between Kog-Ma and Chiang-Mai (ΔT_min) changed seasonally. Thus, assuming a constant lapse rate throughout the year could cause large errors in extrapolating T_min data in mountainous areas in northern Thailand. The difference ΔT_min was related to nighttime net radiation (Rn), suggesting that nocturnal drainage flow affects the determination of ΔT_min. This relationship would be useful in formulating seasonal changes in the lapse rate for T_min. As Rn data are generally unavailable for meteorological stations, an index that relates to the lapse rate for T_min and is calculated from T_max and T_min data is proposed. This index might be useful for accurately estimating T_min values in mountainous regions in northern Thailand.

DOI： 10.1175/2010JAMC2297.1

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/hyp.7622

Language：English   Publishing type：Research paper (scientific journal)  

The number of abandoned coniferous plantations has increased greatly in recent year across Japan. However, though evapotranspiration greatly affects on available water resources, no study observing evapotranspiration in abandoned plantations has been reported. We observed canopy interception loss for four years in an abandoned coniferous plantation located in the Kasuya Research Forest of Kyushu University. Our results were compared with those obtained for other coniferous forests. The canopy interception loss ratio (interception loss/precipitation) we obtained was 24.9%. The relationship between stem density and interception ratio has previously reported. Indeed, the value we obtained was nearly that calculated based on that reported relationship; this information would be useful for examining whether the relationship derived from previous interception studies in coniferous plantations holds even for abandoned coniferous plantations.

Language：English   Publishing type：Research paper (scientific journal)  

To evaluate the role of stormflow in reducing N retention in forested watersheds, we investigated the inorganic N budget of a Japanese suburban forested watershed for 4 years where the proportion of direct flow to precipitation is considerably high (mean is 33%; range is 25-42%). Soil net N mineralization and net nitrification were also measured at middle and lower positions of a slope within the watershed to evaluate nitrate (NO ₃^-) pool size. Annual mean N deposition via throughfall plus stemflow was 15.5 kg N ha^-1 yr^-1 (13.6-17.1 kg N ha^-1 yr^-1), which exceeded the threshold value to potentially induce N leaching from forested watersheds. Net nitrification at the middle position was comparable with the lower position. This suggests that the NO₃^- rich area is large, which could be partly caused by comparable soil moisture conditions with the lower position due to rising groundwater levels during storm events. Annual mean N export was 10.4 kg N ha^-1 yr^-1 (7.8-12.5 kg N ha^-1 yr^-1), and subsequent N retention was distinctly low 33% (12-53%). Stormflow accounted for more than 80% of total annual N export. Furthermore, N retention was lower (12 and 27%) in years with higher proportions of direct flow than in years with lower proportions (36 and 53%). Therefore, stormflow is a significant factor in reducing N retention in forested watersheds. The effect of stormflow observation on the comparison of N budgets in other watersheds with different climate and/or hydrologic conditions is discussed.

DOI： 10.1029/2009JG000944

Language：English   Publishing type：Research paper (scientific journal)  

Light capture efficiency (E_a) and mass-based daily carbon gain (A_mass) were compared between saplings of a deciduous tree species, Ficus erecta Thunb. and the co-occurring evergreen broadleaved tree species, Neolitsea aciculata (Bl.) Koidzumi, in a temperate forest in Japan. Using obtained data and an ecophysiologicalarchitectural model, we calculated the E_a and A_mass of each study sapling. We also analysed the response of A_mass to changes in photosynthetic traits and E _a. Saplings of F. erecta had a higher A_mass than N. aciculata, due to the high leaf area:aboveground mass ratio (LAR). The model calculation suggested that changes in photosynthetic traits and E_a changed A_mass but did not modify the interspecific difference of A_mass. In winter A_mass was lower than that in the growing season due to low light availability during the short day lenght, suggesting modest importance of winter carbon gain for the evergreen saplings of N. aciculata. In conclusion, the advantage of this deciduous species for carbon gain over the co-occurring evergreen broadleaved saplings is not modified by acclimative changes in leaf physiology, crown architecture or prolonged photosynthesis period by evergreen broadleaved trees.

DOI： 10.1071/FP09168

Language：English   Publishing type：Research paper (scientific journal)  

Researchers and journalists in Japan recently proposed forest management as an alternative to dam reservoir development for water resource management. To examine the validity of the proposal, we compared the potential low-flow increase due to forest clearcutting with the increase due to dam reservoir development. Here, we focused on forest clearcutting as an end member among various types of forest management. We first analyzed runoff data for five catchments and found a positive correlation between annual precipitation and the low-flow increase due to deforestation. We then examined the increase in low-flow rates due to dam reservoir development (dQ_d) using inflow and outflow data for 45 dam reservoirs across Japan. Using the relationship between annual precipitation and the low-flow increase due to deforestation, we estimated the potential increase in the low-flow rate for each dam reservoir watershed if forests in the watershed were clearcut (dQ_f). Only 6 of the 45 samples satisfied dQ_f > dQ_d, indicating that the potential increase in the low-flow rate due to forest clearcutting was less than the increase due to dam reservoir development in most cases. Twenty-five of the 45 samples satisfied dQ_f < 0.2 dQ_d, indicating the potential increase in the low-flow rate due to forest clearcutting was less than 20% of the increase due to dam reservoir development in more than half the cases. Therefore, forest management is far less effective for water resource management than dam reservoir development is in Japan.

DOI： 10.1016/j.jenvman.2009.10.011

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.4005/jjfs.92.54

Language：English   Publishing type：Research paper (scientific journal)  

To investigate the effects of storm flow samplings on the evaluation of DIN and SO₄ ^2- budgets, we conducted storm flow samplings and discrete interval (weekly) samplings of stream water, throughfall, and stemflow. This investigation lasted for three years and took place in a small forested watershed in western Japan. Annual exports were calculated by the sum of the load (∑L_total)sum of the discharge (∑Q_total) relationships obtained by storm flow samplings. These were then compared to calculated ones that were based on LQ relationships obtained by discrete interval sampling. The results of discrete interval sampling showed that the relationships of DIN or SO₄ ^2- concentration to the discharge amount found in stream water differed from those of storm flow sampling. This was especially notable in years with higher annual precipitation and subsequent higher annual discharges. Also, exports of DIN and SO4 ²during storm flow periods accounted for 83% and 78% of annual exports on 3-year averages, respectively. These results confirmed that storm flow samplings are essential for estimating annual exports of DIN and SO₄ ^2-. Annual exports that were calculated based on just discrete interval sampling (46% and 17%, respectively) overestimated DIN and SO₄ ^2- from discrete interval and storm flow samplings on a 3-year average. These overestimates were pronounced in years of higher discharge, and critically affected the rates of net-retention or export of DIN and SO₄ ^2-. The relationship of smaller input than output of DIN was reversed if storm flow sampling was included.

DOI： 10.1002/hyp.7557

Language：English   Publishing type：Research paper (scientific journal)  

Land levelling is an important process of the agricultural land consolidation projects. The land levelling process starts by determining the appropriate levels of the terrain and solves the earthwork allocation for the predetermined terrain levels. The recent attempt, reported in the literature, to find an optimal process is a GIS-based approach which solves the transportation problem by determing the designed terrain level and optimal hauling distances that result in the lowest hauling cost. In this study, the Vogel approximation method (VAM) was adopted in initializing the solution to the transportation problems, and the optimization of the solutions obtained by the VAM was examined using the modified distribution method (MODI). To verify the reliability of this combined method, a case study was carried out based on the proposed land levelling project at the Lixian District of Beijing, China. The results show that the optimal average hauling distance calculated from the proposed linear programming model is 79.53m shorter than that estimated using the empirical method, and the unit cost calculated from the linear programming model is 33.4% lower than the experienced cost. The improvements in the optimization of the hauling distance show that the cost of the agricultural land levelling can be efficiently lowered if an appropriate linear programming model is used.

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

We investigated the spatial and seasonal variations in throughfall (Tf) in relation to spatial and seasonal variations in canopy structure and gross rainfall (Rf) and assessed the impacts of the variations in Tf on stand-scale Tf estimates. We observed the canopy structure expressed as the leaf area index (LAI) once a month and Tf once a week in 25 grids placed in a Moso bamboo (Phyllostachys pubescens) forest for 1 year. The mean LAI and spatial variation in LAI did have some seasonal variations. The spatial variations in Tf reduced with increasing Rf, and the relationship between the spatial variation and the Rf held throughout the year. These results indicate that the seasonal change in LAI had little impact on spatial variations in Tf, and that Rf is a critical factor determining the spatial variations in Tf at the study site. We evaluated potential errors in stand-scale Tf estimates on the basis of measured Tf data using Monte Carlo sampling. The results showed that the error decreases greatly with increasing sample size when the sample size was less than ~8, whereas it was near stable when the sample size was 8 or more, regardless of Rf. A sample size of eight results in less than 10% error for Tf estimates based on Student's t-value analysis and would be satisfactory for interception loss estimates when considering errors included in Rf data.

DOI： 10.1002/hyp.7473

Language：English   Publishing type：Research paper (scientific journal)  

In this study, we aimed to assess how sample sizes affect confidence of stand-scale transpiration (E) estimates calculated from sap flux (F_d) and sapwood area (AStree) measurements of individual trees. In a Japanese cypress plantation, we measured F_d and A_S-tree in all trees (n = 58) within a 20 × 20 m study plot, which was divided into four 10 × 10 subplots. We calculated E from stand A_S-tree (A _S-stand) and mean stand F_d (JS) values. Using Monte Carlo analyses, we examined the potential errors associated with sample sizes in E, A_S-stand and JS using the original A_S-tree and F _d data sets. Consequently, we defined the optimal sample sizes of 10 and 15 for A_S-stand and JS estimates, respectively, in the 20 × 20 m plot. Sample sizes larger than the optimal sample sizes did not decrease potential errors. The optimal sample sizes for JS changed according to plot size (e.g., 10 × 10 and 10 × 20 m), whereas the optimal sample sizes for A_S-stand did not. As well, the optimal sample sizes for JS did not change in different vapor pressure deficit conditions. In terms of E estimates, these results suggest that the tree-to-tree variations in F_d vary among different plots, and that plot size to capture tree-to-tree variations in F_d is an important factor. The sample sizes determined in this study will be helpful for planning the balanced sampling designs to extrapolate stand-scale estimates to catchmentscale estimates.

DOI： 10.1093/treephys/tpp074

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.agrformet.2010.08.011

Other Link： http://www.sciencedirect.com/science/article/pii/S016819231000225X

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Although sap flux measurement is one of the most robust techniques for stand-scale transpiration estimates, its applicability to bamboo is unclear. Ultimately we aim to establish a method for sap flux-based stand-scale transpiration estimates in a bamboo forest This study focused on establishing a method for individual-scale transpiration estimates. We conducted sap flux measurements using hand-made 1-cm length sensors, and water absorption measurements in cut-bamboo. The sensors could detect water uptake in individual plants (i.e., sap flux in moso bamboo). The diurnal changes in sap flux density reasonably well corresponded to those in water absorption. We found there was an underestimation of whole-tree water use with the 1-cm Grainer sensor; thus we suggested a modified equation for the calculation of sap flux density. In this study we could estimate individual-scale transpiration in moso bamboo using sap flux measurements.

Language：English   Publishing type：Research paper (scientific journal)  

This study was undertaken to identify critical and practical factors explaining spatial variations in soil respiration and to estimate stand-scale soil respiration in an aseasonal tropical rainforest on Borneo Island. To this aim, we conducted soil respiration measurements at 25 points in a 40 m × 40 m subplot of a 4 ha study plot between 2002 and 2006, and examined the spatial variation in soil respiration averaged over the 4 years in relation to soil, root, and forest structural factors. In addition, we examined the spatial representativeness of soil respiration measured in the subplot using a specific scaling procedure. Consequently, we found significant positive correlation between the soil respiration and forest structural parameters such as the mean diameter at breast height (DBH), total basal area, and maximum DBH within 6 m of the measurement points. The most important factor was the mean DBH within 6 m of the measurement points, which had a significant linear relationship with soil respiration. Using the derived linear regression and an inventory dataset, we estimated the 4 ha plot-scale soil respiration. The 4 ha plot-scale estimation (6.0 μmol m^-2 s^-1) was nearly identical to the subplot-scale measurements (5.7 μmol m^-2 s^-1), which were roughly comparable to the nocturnal CO₂ fluxes calculated using the eddy covariance technique. In addition, we discuss characteristics of the stand-scale soil respiration at this site by comparing with those of other forests reported in previous literature in terms of the soil C balance. Soil respiration at our site was noticeably greater, relative to the incident litterfall amount, than soil respiration in other tropical and temperate forests probably owing to the larger total belowground C allocation by emergent trees. Overall, this study suggests the arrangement of emergent trees with larger DBH and their belowground C allocation could be primary factors controlling spatial variations in soil respiration in the tropical rainforest.

DOI： 10.1016/j.agrformet.2009.05.007

Language：English   Publishing type：Research paper (scientific journal)  

For evaluating the effect of coniferous plantation thinning on water resources, our previous study (Komatsu et al., 2007c) developed a model for predicting changes in annual evapotranspiration caused by coniferous plantation thinning. This model is comprised of transpiration and interception evaporation parts. The model needs to be verified from three viewpoints, stability of transpiration amounts with thinning, decrease in interception evaporation amounts with thinning, and applicability of the model to catchment scale. This study mainly focused on verification of the interception evaporation part. Based on seven datasets of interception evaporation derived from earlier publications, we compared model prediction results with the observed results. Model prediction results agreed fairly well with the observed results, indicating validity of the interception evaporation part of the model. Based on one dataset for verifying applicability of the model to catchment scale, model prediction results agreed fairly well with the observed results, implying applicability of the model to catchment scale. We should note that validity of the transpiration part of the model was not examined. Applicability of the model to catchment scale was not fully examined due to lack of observation data. Thus, we raised observation data that should be required for further model verification and presented guidelines for future observation studies.

Language：English   Publishing type：Research paper (scientific journal)  

The amount of water stored in the stem introduces uncertainty when estimating diurnal whole-tree transpiration (E_T) and canopy stomatal conductance (G_C) using sap flow measured at the base of the stem (Q). Thus, to examine how E_T can be calculated from Q, we obtained E_T using sap flow and stem water content measurements and a whole-tree water balance equation, and compared it with Q. In this study, we measured sap flows in 33-year-old individual trees of Cryptomeria japonica D. Don and Chamaecyparis obtusa Endl. using constant-heat sap flow probes. Sap flows were measured at several depths at the base of the stem, and at the upper trunk as a surrogate of E_T. Stem water contents were measured at three vertical positions on the trunk using amplitude-domain reflectometry (ADR) sensors. We also measured sapwood volumes of the study trees. Using simultaneous sap flow and stem water content measurements along the tree stem, we confirmed that stem water storage has impacts on the transpiration stream. These include sap flow lags along the tree heights and an enhanced peak of transpiration from stem sap flow. These results enabled us to calculate the correct E_T by multiplying Q by 1.18 and shifting its time series forward by 30 min. The E_T value was then used to calculate G_C for both tree species. The factor of 1.18 is based on the fact that at noon, the value of E_T was higher than that of Q, due to the prolonged Q during the evening. Establishing the time lag was relatively simple and was determined by comparing Q and vapor pressure deficit. The multiplier is more challenging to ascertain due to the difficulty in obtaining E_T correctly.

DOI： 10.1002/hyp.7338

Language：English   Publishing type：Research paper (scientific journal)  

Converting coniferous plantations to broad-leaved forests is believed to result in increased runoff in Japan. This study examined low-flow changes in runoff in the Tatsunokuchi-Minami catchment, located in a region with summer precipitation, caused by the conversion of a coniferous plantation to a broad-leaved forest. We compared the flow duration curves for the coniferous plantation period with those for the broad-leaved forest period. We observed no evidence of increased low flows according to the change in forest type. Thus, the commonly held belief was not supported by the results from a summer precipitation region with respect to low-flow rates.

DOI： 10.1002/eco.50

Language：English   Publishing type：Research paper (scientific journal)  

Hydrologic balance in high-altitude, mid-latitude mountain areas is important in terms of the water resources available to associated lowlands. This study examined how current and historical shifts in precipitation (P) patterns and concurrent increases in temperature (T) affected runoff (Q) and other hydrologic components in a mid-latitude mountain catchment of central Japan, using a combination of long-term data and a simplified hydrologic model, along with their stochastic treatment. The availability of intensive meteorological and hydrological data from the period 1997-2001 allowed the derivation of key relationships for the current climate that tie the forcing term to the parameters or state variables. By using the data recorded in the period 1965-2001, the force for driving the historical simulation was generated. Based on this model and historical shifts in P and T, the probability density functions of Q (pdf(Q)) was computed. A main novelty in this study is that such a stochastic representation, which is useful for considering the influence of projected shifts in environmental factors on the hydrologic budget, was provided. Despite the large increase in the rate of T in winter and spring, pdf(Q) in spring and summer varied appreciably during the time studied mainly because of an increase in snowmelt. An interannual change in whole-year Q was robust to shifts in T because while Q in spring increased, in summer it decreased, implying a crucial effect of global warming on mountain hydrologic regimes is change in the timing of Q.

DOI： 10.1002/hyp.7264

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

In recent years, moso bamboo (Phyllostachys pubescens) forest areas in Japan have rapidly expanded, and bamboo is now invading nearby natural or plantation forests. To date, only one study has examined the rainfall interception of a moso bamboo forest. In that study, it was reported that the interception ratio (interception/rainfall) of the bamboo forest did not exceed the interception ratios of other natural and plantation forests (n = 4) in Japan. To expand the current state of knowledge about rainfall interception of bamboo forests, we measured throughfall and stemflow at another bamboo forest site. Annual rainfall (Rf), throughfall (Tf), and stemflow (Sf) during the measurement period were 2,105, 1,556, and 322 mm, respectively. Annual rainfall interception at the plot (I) was 228 mm. Tf/Rf, Sf/Rf, and I/Rf were 73.9, 15.3, 10.8%, respectively. I/Rf was less than 20% throughout the year except in October, the month with lowest rainfall. We also summarized rainfall interception data from 19 other natural and plantation forests. The I/Rf value of our site did not exceed the I/Rf values of these natural and plantation forests (n = 19). Our data will be useful for assessing changes in water resources that result from replacement of natural or plantation forests by bamboo forests.

DOI： 10.1007/s10310-008-0108-2

Language：English   Publishing type：Research paper (scientific journal)  

Japanese cypress (Chamaecyparis obtusa) is one of the most common plantation species in Japan. In most Japanese cypress plantations, closure of the forest canopy hinders understory growth because of insufficient management practices. Thus leaf litter barely covers the soil surface. Such plantations are vulnerable to surface erosion triggered by rainfalls, and could yield large amounts of suspended sediment (SS). However, few studies have investigated the annual SS yield. This study aimed to develop a modified model of SS yields, and to accurately estimate and characterize the annual SS yield from a Japanese cypress plantation. For this, hydrological surveys were conducted for 5 years, and stream water was sampled weekly as well as sequentially at 15-60 min intervals in each of 14 rain events in a small forested watershed of Japanese cypress. The root mean square error (RMSE) and the annual SS yield estimates were obtained using three different equations: the rating curve derived from instantaneous SS concentration versus stream discharge relationship (SSC - Q equation); the rating curve derived from cumulative SS yield versus cumulative specific discharge relationship (∑SS - ∑Q equation); and the multiple regression of cumulative SS yield expressed as functions of cumulative specific discharge and antecedent rainfalls (∑SS - ∑Q × AR equation). The ∑SS - ∑Q × AR equation is a modified model considering the effects of antecedent rain history on the SS yield. The parameters in each equation were determined by a nonlinear least square method. Of the three equations, the RMSE was the highest using the SSC - Q equation. Although the ∑SS - ∑Q equation and the ∑SS - ∑Q × AR equation gave similar RMSE values, the SS yields extrapolated by the ∑SS - ∑Q equation would be overestimated. Thus, the 5-year average of annual SS yield estimated by the ∑SS - ∑Q equation was three times larger than that estimated by the ∑SS - ∑Q × AR equation. These results indicate that the ∑SS - ∑Q × AR equation more accurately estimates the annual SS yield, compared with the other two equations. The results also suggest that antecedent rain history, as well as stream discharge, should be considered for appropriately estimating the annual SS yield. The annual SS yield estimated by the ∑SS - ∑Q × AR equation was the largest among 25 undisturbed forested watersheds, except for two watersheds dominated by sandstone. Our results suggest that the annual SS yield is greater from a Japanese cypress plantation under current management practices than from other undisturbed forests.

DOI： 10.1016/j.foreco.2009.02.011

Language：English  

DOI： 10.1142/9789814280969_0003

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.3178/jjshwr.21.414

Language：English   Publishing type：Research paper (scientific journal)  

Plant-soil system patterns and processes along a slope are among the greatest causes of uncertainty in estimating watershed-scale transpiration (E). Tree-to-tree and radial variations in xylem sap flux density (F_d), in addition to tree biometrics, were measured over a 2-year period (2005-2006) in two slope stand positions. The areas of interest consisted of an upper slope plot (UP) and a lower slope plot (LP) in a Japanese cedar (Cryptomeria japonica D. Don) forest watershed and the environmental controls of stand E for each plot were compared. Canopy stand E (E_C) and canopy stomatal conductance (G_C) in the UP were less than those in the LP during the growing season, while those in the UP were greater than those in the LP over winter. In addition, mean stand F_d (J_S) in the UP was greater than that in the LP over winter, but J_S values were similar in the UP and LP except in the winter, which allows us to extrapolate watershed-scale E based on J_S estimated from F_d measurements of a partial stand in the watershed. However, this relationship contains a bias and differed between 2005 and 2006. Although there were significant differences in soil moisture conditions between the UP and LP in both years, a systematic relationship between the similarity in J_S and soil moisture conditions was not found. The bias was due to a tendency for J_S in the LP to be greater than that in the UP in 2006. This tendency was amplified because J_S in the LP was greater than that in the UP around an atmospheric humidity deficit (D) of 1-1.5 kPa and frequencies of this D range were higher in 2006 than in 2005. The greater J_S in the LP at D ∼ 1-1.5 kPa could be explained by the difference in the response of G_C to D between the UP and LP. Our results suggest this to be the cause of the similarity in J_S values for the UP and LP and for the occasional abortion of its similarity. However, even when the bias or the occasional deviation is disregarded, the error in estimating stand E from a partial stand is so small that it is comparable to an F_d measurement error. For example, the error when using only the LP was 6.6% for stand E.

DOI： 10.1016/j.agrformet.2008.04.010

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Several previous studies in Japan have examined differences in rainfall interception amounts induced by differences in forest properties by comparing the annual rainfall interception ratios (annual rainfall interception divided by annual rainfall) from various sites without considering variations in meteorological conditions between sites. Rainfall interception actually depends on meteorological conditions as well as forest properties. This study examined variations in the annual interception ratio relating to the variation in annual rainfall, which would be the primary factor relating to the interception ratio, across Japan with the use of a rainfall interception model assuming the same forest properties (i.e., the canopy storage capacity, canopy closure, leaf area index (LAI), and the bulk coefficient for sensible heat transfer). The ratio ranged between 0.12 and 0.24 across Japan and was highly correlated to annual rainfall. This indicates that considering the variation in annual rainfall is critical for assessing the difference in rainfall interception amounts induced by forest properties. We reconsidered the results of previous studies in Japan that compared annual interception ratios between sites with different forest properties: (i) there is no clear difference in interception amounts between broadleaf and coniferous forests and (ii) there is a positive correlation in stem density and interception amounts for coniferous forests. These results still held when considering differences in annual rainfall between sites.

DOI： 10.1016/j.foreco.2008.06.036

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

This study aimed to clarify the effects of antecedent rain history on particulate phosphorus (PP) loss in a small mountainous watershed covered primarily with a plantation forest of Japanese cypress (Chamaecyparis obtusa). We analyzed stream discharge and PP concentration at 15-60 min intervals during 24 h in eight rain events with different discharge levels. The PP concentration versus stream discharge (PPC-Q) relationships exhibited clockwise hysteresis loops for each of the eight events monitored. Discharge could explain changes in PP concentration on the falling but not rising limb of the hydrograph. On the rising limb, a positive relationship between the rate of changes in discharge (dQ/dt) and the PP load (dL/dt) was found for each event. This indicates that a large amount of PP is strongly pulsed at times of rapidly increased discharge. These results suggest that dQ/dt is the driving force behind PP supply and the primary control on the clockwise hysteresis loop of PPC-Q relationship. There was a strong negative correlation between the antecedent precipitation index and the slope of the dL/dt versus dQ/dt relationship. This shows that a rapid increase in PP load occurs even with slight increases in discharge as antecedent moisture conditions become drier. The soil water repellency and rapid runoff response following dry conditions support that soil desiccation increases the PP supply associated with soil erosion via overland flow. Therefore, we concluded that the antecedent rain history affects the mobility of PP via soil desiccation. The findings of this study will fill gaps in our understanding of temporal variations in released fine sediment and associated PP as reported in previous studies.

DOI： 10.1016/j.jhydrol.2008.01.012

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

Language：English   Publishing type：Research paper (scientific journal)  

This study examined the change of water yield when a broad-leaved forest is converted to a coniferous plantation forest after clear-cutting in northern Japan where monthly precipitation is evenly distributed. Annual water yield after clear-cut was greater than observed in a broad-leaved forest and then decreased with the growth of a coniferous plantation forest. This reduction ceased after 30 years from the planting of coniferous seedlings. Water yield of a coniferous forest at this stage was smaller than observed in a broad-leaved forest. Results from monthly water yield examinations suggested that the difference in annual water yield was primarily caused by the difference in winter interception loss between broad-leaved deciduous and coniferous evergreen forests. The above results suggest that converting coniferous forests into broad-leaved forests can be used to increase water yield in these regions.

DOI： 10.1016/j.foreco.2007.10.010

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

Language：English   Publishing type：Research paper (scientific journal)  

We investigated the sapling leaf display in the shade among trees of various leaf lifespans co-occurring under the canopy of a warm-temperate conifer plantation. We measured leaf-area ratio (aLAR) and morphological traits of saplings of evergreen broadleaved tree species and a deciduous tree species. Although we found large interspecific and intraspecific differences in aLAR even among saplings of similar size in the homogeneous light environment, we did not find a consistent trend in aLAR with leaf lifespan among the species. While deciduous trees annually produced a large leaf area, some evergreen broadleaved trees retained their leaves across years and had aLAR values as high as those of deciduous trees. Among leaf-level, shoot-level, and individual-level morphological traits, aLAR was positively correlated with current-year shoots mass per aboveground biomass in deciduous trees, and with the area of old leaves per aboveground mass in evergreen broadleaved trees. Thus, tree-to-tree variation in the degrees of annual shoot production and the accumulation of old leaves were responsible for the interspecific and intraspecific variations in aLAR.

DOI： 10.1007/s10310-007-0049-1

Language：English   Publishing type：Research paper (scientific journal)  

To estimate whole-tree water use when employing sap flow measurements, integration of the sap flux density (F_d) over the sapwood area is needed. Accordingly, it is necessary to obtain information on the characteristics of stem water transportation such as spatial variations in F_d and the active xylem area in the stem cross-section. Although evergreen oak trees with radial-porous wood represent a major component of secondary forests in western Japan, detailed information on their stem water transportation characteristics remains unclear. In the present study, we used the heat dissipation method (Granier method) to conduct measurements of azimuthal and radial variations in the F_d of Quercus glauca Thunb. ex Murray, a representative evergreen broad-leaved tree in western Japan. Further, by analyzing the anatomy of the xylem structure, we examined why F_d varies spatially in the stem cross-section. By using a dye solution injected into a radial hole bored into the tree trunk, we confirmed that the entire stem is hydroactive. We also compared the spatial variations in F_d and water conductivity per xylem area (K_s) which were estimated by using the observed vessel diameters and their density over the stem cross-section and Hagen-Poiseuille's law. Azimuthal and radial variations in F_d reached about 60 and 50% of the maximum values, respectively, and could be explained by spatial variation in K_s. As a result, we obtained statistical parameters describing the spatial variation in F_d in Q. glauca and determined that whole-tree water use estimated from measurements in one direction had at most ±20% potential errors for studied trees.

DOI： 10.1007/s00468-007-0165-8

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

In Japan, forested areas are usually located upstream of urban and agricultural areas. Estimating annual water yield from such forested areas is therefore crucial for water resources management. For this purpose, estimating annual forest evapotranspiration is required. We developed an empirical model for estimating annual forest evapotranspiration E in Japan based on 43 catchment water balance datasets summarized from earlier publications. The model formulated E as E (mm) = 31.4T (°C) + 376, where T is mean annual air temperature. This model estimated E observed in forest catchments with an average 6% error relative to incident annual precipitation. This error was comparable to or smaller than the error included in precipitation data due to the spatial heterogeneity of precipitation. High-quality air temperature data are commonly available in Japan, thus this model is a practical tool for annual water yield estimates from forested areas and therefore water resources management.

DOI： 10.1016/j.jhydrol.2007.10.006

Language：English   Publishing type：Research paper (scientific journal)  

Recently, catchment water balance measurements have not been used actively for examining forest evapotranspiration compared to process-based measurements based on meteorological and sap-flow methods. This paper overviewed the history of forest evapotranspiration studies and clarified what caused this situation. This paper then pointed out that catchment water balance measurements cannot be replaced completely by process-based measurements from the viewpoints of data accuracy and feasibility of measurements. This paper also pointed out that coordination of process-based measurements and catchment water balance measurements brings new insights. Furthermore, this paper proposed several important topics that should be examined by such coordination and also proposed measures to develop environments that promote such coordination.

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Many studies have reported tree growth reduction in forests with pedestrian trampling, implying a reduction of tree transpiration in such forests. We undertook observations of tree transpiration based on the heat-pulse method in a forest (Lithocarpus edulis) with pedestrian trampling. We prepared trampled and control plots in the forest. Tree transpiration in the trampled plot was reduced compared to that in the control plot after precipitation with a small-precipitation period preceding this. No difference was observed between plots in the small-precipitation period itself; during which tree transpiration was limited in both plots. After the period, tree transpiration recovery was not as complete in the trampled plot as in the control plot. This was caused by incomplete soil matric potential recovery at 20 cm and deeper in the trampled plot due to a lower infiltration rate. We believe this study is the first to report reduction of tree transpiration in a forest with pedestrian trampling.

DOI： 10.1016/j.agrformet.2007.04.014

Language：English   Publishing type：Research paper (scientific journal)  

We measured the photosynthetic capacity (RuBP carboxylation and electron transport capacity at 25°C) and the maximum photochemical efficiency (F _v/F_m) from autumn to spring in saplings of two evergreen broadleaf tree species and examined the negative effects of photoinhibition on the photosynthetic capacity. Saplings were grown in pots under three simulated natural light environments typical of temperate forests: an open site, deciduous understorey and evergreen understorey. During winter, the photosynthetic capacity and F_v/F_m synchronously decreased in leaves in the sun, but not those in the shade. We found large differences in F _v/F_m and photosynthetic capacity, along with a positive correlation between F_v/F_m and the photosynthetic capacity among leaves in different light environments. In photoinhibited leaves that were transferred to the shade in mid-winter, photosynthetic capacity increased synchronously with the increment of F_v/F_m. The decrease in photosynthetic capacity in photoinhibited leaves and the synchronous recovery of photosynthetic capacity with photoinhibition supported the hypothesis that photoinhibition depressed the photosynthetic capacity during winter. We showed that difference in the degree of photoinhibition was responsible for the different winter photosynthetic capacity among leaves exposed to different light environments.

DOI： 10.1071/FP06312

Language：English   Publishing type：Research paper (scientific journal)  

Annual ring growth of Quercus liaotungensis trees in natural forests bounded by desertified region in the Loess Plateau of China was investigated for the evidence of climatic influence. Increment cores were sampled and cross-dated for 120 trees from six stands 0.5-2.5 km apart. Site tree-ring chronologies were created using general dendrochronological techniques. The results of correlation analyses between tree-ring indices and monthly climatic variables indicated that radial growth was positively correlated with precipitation in September of the previous year and that from April to June of the current year. Ring widths were negatively affected by temperature during spring and summer. In contrast, mild temperature in the previous October showed a positive influence. The results suggest that precipitation is important in the early growing season when soil and air are dry, and that high temperatures tend to reduce radial growth in this region. September rainfalls and a warm October may provide conditions that facilitate carbon storage, favor soil microbial activity, and promote root growth and shoot maturation against detrimental effects of stresses in the following seasons. There were also some differences among plots in the effects of both climatic variables probably as a result of different structures and geographical conditions that modified microenvironments. The results may contribute to the reforestation management of the area. It is expected that Q. liaotungensis forests should be ecologically established in this region on shady and half-shady slopes where air and soil drought stresses are not serious.

DOI： 10.1016/j.dendro.2007.01.005

Language：English   Publishing type：Research paper (bulletin of university, research institution)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Chemical characteristics of precipitation and streamwater at the Ashoro Research Forest and Kasuya Research Forest

Language：English   Publishing type：Research paper (scientific journal)  

Litterfall production, the amount of organic matter on the forest floor, and litter decomposition rates were studied in an exotic nitrogen (N)-fixing black locust (Robinia pseudoacacia) plantation and an indigenous non-N-fixing oak (Quercus liaotungensis) forest near Yan'an, on the Loess Plateau, China. The chemical composition of litterfall and soil was also examined. Litterfall production was similar in the two forests; however, the amount of N in litterfall was greater in the black locust plantation than in the oak forest because of the high N concentration of black locust leaves. The decomposition rate of black locust leaves was higher than that of oak leaves, most likely because of the higher N content of black locust leaves. These results suggested that N cycling was greater and faster in the black locust plantation than in the oak forest. However, faster decomposition caused the disappearance of the organic layer from the forest floor in the black locust plantation. Furthermore, despite greater N cycling in the black locust plantation, the soil N content was lower than in the oak forest. Our results indicated that the black locust plantation might be more susceptible to soil erosion than the oak forest. In addition, our study suggested that the black locust plantation had advantages in short-term N uptake, growth, and N cycling; however, it had disadvantages in soil development and regeneration and sustainable land management.

DOI： 10.1016/j.foreco.2006.12.026

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The behavior of dissolved and particulate components of stream nitrogen (N) and phosphorus (P) were measured for 2 years in a small mountainous watershed covered primarily with a plantation forest of Japanese cypress (Chamaecyparis obtusa). The load of dissolved N and P bore a consistent relationship to discharge while the load of particulate N and P varied by up to two orders of magnitude at a given discharge level. Most N was exported in a dissolved form (DN) while most P was exported in a particulate form (PP), which bears similarity to loads from agricultural watersheds. Owing to the different behaviors of DN and PP, changes in the total nitrogen (TN) load were primarily attributed to variations in discharge unlike changes in the total phosphorus (TP) load. High flow conditions, resulting from heavy rainfall, displayed PP release significantly larger than expected. The TP load in high flow conditions was severely underestimated using a regression equation expressed as a function of discharge, which was based on the weekly sampling data biased toward low flow conditions. In addition, the TN load during peak discharges in heavy rain events was underestimated by the regression equation because of unpredictable increases in the particulate component. Our study shows that the particulate component ratio determines whether discharge can explain changes in load regardless of chemical species. The results suggest that plantation forests in rainy regions can be a diffuse source of particulate nutrients depending on soil surface conditions.

DOI： 10.1007/s10310-006-0250-7

Language：English   Publishing type：Research paper (scientific journal)  

We determined the amount of information needed to estimate watershed-scale transpiration in a Japanese cedar (Cryptomeria japonica D. Don) forest from sap flow measurements of individual trees. Measurements of tree biometrics (diameter at breast height (DBH) and tree sapwood area (A_{S_tree})), and tree-to-tree and radial variations in xylem sap flux density (F_d) were made in two stand plots, an upper slope plot (UP) and a lower slope plot (LP), during a growing season characterized by significant variations in environmental factors. We then investigated how mean stand sap flux density (J_S) and a tree stem allometric relationship (DBH-A_{S_tree}) varied between the stands. Appropriate sample sizes for estimating representative J_S values were determined. Both a unique and a general function allowed description of the allometric relationship along the slope, but the data for its formulation was required for both the UP and LP. Values of J_S in the UP and LP were similar during the study period despite differences in tree density and size between the plots, implying that J _S measured in a partial stand in a watershed is a reasonable estimate of J_S in other stands in the watershed, and that stand sapwood area calculated from A_{S_tree} is a strong determinant of water use in a forest watershed. To estimate J_S in both the UP and LP, it was necessary to sample at least 10 trees in each plot.

DOI： 10.1093/treephys/27.2.161

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.4005/jjfs.88.473

Language：English   Publishing type：Research paper (scientific journal)  

The light environment and growth traits of the pioneer tree species Litsea citriodora in a recently clear-cut plantation were investigated in order to reveal the establishment process and growth of this species under annual weeding after clear-cutting. We investigated the light environments and the morphology, physiology and aboveground architecture of L. citriodora saplings in a plot that included both clear-cut open areas and forest floor under a conifer canopy. Dense populations of L. citriodora saplings were found in the open sites but few were observed on the forest floor. Saplings that originated from old stumps (sprout-saplings) were tall in height and dense, but seedlings were sparse and lower in height than the competitive tall herbaceous species Solidago altissima. Saplings of L. citriodora showed a higher leaf area per aboveground mass and greater area-based photosynthetic capacity than saplings of the co-occurring pioneer tree species Mallotus japonicus and Clerodendron trichotomum. Moreover, the L. citriodora saplings had a main stem with a larger length per mass ratio and more efficiently elongated per unit aboveground mass than M. japonicus and C. trichotomum. Sprout-saplings of L. citriodora attained rapid vertical elongation with rapid biomass acquisition as a result of their aboveground shoot architecture, allowing competition with S. altissima. Clear-cutting and subsequent weeding not only created open sites favorable for this pioneer tree, but also promoted the formation of sprouts, allowing sprout-saplings with rapid vertical growth to successfully establish in the clear-cut zone by inhibiting complete coverage by other pioneer trees.

DOI： 10.1016/j.foreco.2006.09.010

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.agrformet.2005.11.007

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.foreco.2004.10.066

Language：English   Publishing type：Research paper (scientific journal)  

The stem water conducting system of an evergreen broad-leaved oak, Lithocarpus edulis (Mak.) Nakai, was investigated. Evergreen broad-leaved oaks (Lithocarpus, Castanopsis, Cyclobalanopsis, Quercus) belonging to the Quercoideae are a major component of Asian monsoon forests, and are characterized by the possession of radial-porous wood. A characteristic of radial-porous wood is the development of aggregate rays between radially oriented files of vessels. We measured the distribution of vessel lumen diameters in a stem cross section and calculated the theoretical water conductivity of the wood. The radial profile of the heat pulse velocity (HPV) was measured for an intact whole tree under field conditions and compared with the theoretical distribution of water conductivity. Soft X-ray photographs of frozen stem sections indicated that most of the vessel lumina were filled with water, including those of vessels more than 20 years old. Even when vessels were relatively wide (lumen diameters > 100 μm), cavitation was negligible. The rate of water uptake from the cut stem base correlated closely with HPV (r = 0.96), and HPV closely reflected the mean volume flow per stem sectional area (SFV
_s
) around the sensor probes. However, the ray tissue sharply inhibited heat transfer, and the positioning of the probes strongly affected the absolute value of HPV. It was also found that HPV more closely reflected the mean sap flow velocity in the vessels than did SFV
_s
.

DOI： 10.1093/treephys/25.2.221

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/hyp.5746

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10333-003-0029-9

Language：English   Publishing type：Research paper (scientific journal)  

In this paper, we tried to diagnose the stress that was brought by water shortage and salinization by spectral reflectance. The concentration of chlorophyll and leaf water content with raw leaf of grass was changed by these stresses. Spectral reflectance was influenced by the stresses too. But the pattern of spectral curve changes was not the same for water shortage and salinization. The concentration of chlorophyll was decreased similarly by both stresses. On the other hands, the leaf water content was extremely decreased by water shortage compared to salinization. We couldn't learn the cause of stress using the concentration of chlorophyll as the only index of stress. It is necessary for diagnosis of stress that both concentration of chlorophyll and leaf water content be applied as the indexes of stress. The concentration of chlorophyll and leaf water content could be measured by spectral reflectance not concerned with the kind of stress. The concentration of chlorophyll was estimated by R800nm/R680nm. The leaf water content was estimated by R1200 nm/R1500nm. Application of these indexes makes possible the diagnosis of water shortage and salinization stress by remote sensing.

DOI： 10.2480/agrmet.59.199

Language：English   Publishing type：Research paper (scientific journal)  

Although coarse woody debris (CWD) is an important component of stream ecosystems in forested areas, the processes of CWD distribution, transport, and retention have not been clarified. In this study the distribution process of CWD pieces shorter than the bankfull width (S-CWD) is discussed using an in situ field experiment of log transport and a field survey of CWD distribution in mountain streams. The transport experiment showed that transport distance has a close relation to flow depth and also implied that the magnitude and sequence of a series of flows were important factors for S-CWD transport and retention in streams. The survey of CWD distribution indicated that in-stream obstructions played an important role in the S-CWD retention in deeper channels where S-CWD pieces were potentially transported distances more than spacing between trapping sites of CWD. Overall, the in situ field experiment and the segment- to reach-scaled analysis using h* (=depth/diameter) helped us understand the actual movement and distribution of CWD.

Language：English   Publishing type：Research paper (scientific journal)  

Daily albedos of a bare sand surface were measured with a solarimeter (Eko MS-62) between 23 August and 30 November in 1997 at Tottori sand dune, Japan. These quickly decreased on rainy days, and recovered during dry spells (days between rainfalls). A strong exponential relationship was found between daily albedos and the number of dry days. The daily albedos on dry days also showed a direct relationship with daily transmissivities in the range less than 0.55. Two simple models were developed to estimate daily albedos for dry spell days on bare Tottori sand surface using routinem eteorological data. Daily albedos were calculated using these two models, and compared with the measured daily albedos. For Model #1, the daily albedos were successfully predicted only using the number of dry spell days; the correlation coefficient between the estimated and measured albedo was 0.73, and the standard error was 1.2%. For Model #2, the number of dry spell days and transmissivity were considered in order to calculate the daily albedo on dry spell days; the correlation coefficien was 0.85, and the standard error was 0.9%. Estimated albedos were in good agreement with measured albedos.

DOI： 10.2480/agrmet.57.1

Language：English   Publishing type：Research paper (scientific journal)  

The albedo of Tottori sand dune was measured with a solarimeter (Eko MS-62) and recorded by a data logger Solac-III (Eko). The soil water content (g/g) was measured at various depths a 9:00 a.m. every day. The relationships of albedo with soil water content and solar elevation were determined. The albedo changes with soil water content at the surface and at individual depths by two an three steps, respectively. The albedo decreased linearly with increasing surface soil water content over a small range. Outside that range, the albedo was essentially constant. The albedo appeared to be related strongly to solar elevation in the afternoon on clear days (transmissivity more than 0.55) when the surface soil water content was less than 0.005 g/g at 9:00. This relationship did not exist in the forenoon period due to dew condensation on the sand surface at night. However, the daily distribution of albedo appears to be approximately symmetrical about solar noon in response to solar elevation effects if the soil water content at sunrise is less than 0.005 g/g.

DOI： 10.2480/agrmet.56.217

Language：English   Publishing type：Research paper (scientific journal)  

Most meteorologists have reported that higher order closure models are better than the K-theory model for estimation of environment in the canopy, but solving a higher order closure model requires boundary conditions for turbulence, which is measured directly by a sonic anemometer. However, sonic anemometers are expensive so few scientists in agriculture use high order closure models. In the present research, estimation of the wind profile in and above a sorghum canopy was carried out by use of a 2nd order closure model with mean wind velocity at a single height above the canopy. Comparison between the observed and calculated profiles indicated that the former was well represented by the latter in general. This indicates that the present calculation scheme can be used for estimation of wind profiles in the canopy without observation of the turbulence. It revealed that most large scale turbulence was generated at the upper part of a sorghum canopy during the heading stage, and that measuring the plant area density should be a more important canopy meteorological observation than the leaf area index during theheading stage, since the non-leaf portion of plant area is not negligible.

DOI： 10.2480/agrmet.56.303

Language：English   Publishing type：Research paper (scientific journal)  

The authors have developed a “Earth-Air Heat Exchange Distillation System” for collecting water from vapor originated in evapotranspiration. This system distills water from vapor by cooling the air in a greenhouse, using underground heat exchange pipes. It is similar to “Soil Heat Exchanger-Storage Systems”. A parameter for estimating the daily amount of collected water was investigated, based on heat and vapor budget of the heat exchange pipe. The results indicate that the daily amount of collected water is a linear function of the integrated surplus of air-soil temperature.

DOI： 10.2480/agrmet.55.101

Language：English   Publishing type：Research paper (scientific journal)  

The effect of wind speed on the aerodynamical parameters, namely the zero-plane displacement d and roughness length z₀, and the relationships between d and z₀ is discussed. Experiments conducted in sorghum and alfalfa fields reveal that d decreases and z₀ increases with increasing wind speed or friction velocity. The relations between d and z₀ obtained in these experiments are not well expressed by previous equations that were presented during the last several decades. Thus, new equations representing the relationships between d and z₀, and a newly designed concept for eddy viscosity within the canopy are proposed and experimentally tested in sorghum, alfalfa, and tanukimame fields. The test results demonstrate that calculations from present equations coincide with the observed results. In the tanukimame field, however, the zero-plane displacement and roughness length do not vary with wind speed when the leaf area index LAI is large (LAI=5.6). On this point, it is considered that the dependence of the zero-plane displacement and roughness length on wind speed are influenced by the leaf area index and the drag coefficient for an individual leaf.

DOI： 10.2480/agrmet.55.15

Language：English   Publishing type：Research paper (scientific journal)  

A leaf bulk transfer coefficient for latent heat flux c_e has been formulated as a function of solar radiation, wind speed, and minimum stomatal resistance, and time variations of the sensible heat flux H and the latent heat flux lE over a lawnland for a period of summer three months have been simulated using routine meteorological data(AMeDAS). The calculated results agree well with the observed values: the rms error between the observed and the calculated values of H are ±8 Wm^-2, while those of lE are ± 12 Wm^-2.

DOI： 10.2480/agrmet.53.307

Language：English   Publishing type：Research paper (scientific journal)  

The analysis of the perpendicular structure of vegetation by remote sensing would provide valuable information for classification of vegetation and estimation of the environment. The purpose of this paper is to investigate the relationship between perpendicular structure of vegetation and spectral reflectance in visible and near infrared. The spectral reflectance is measured in the range of 400nm to 2500nm at intervals of 1nm by changing the number of overlap leaves, perpendicular space between leaves, angle of leaf, incident angle and sensor look angle. The results indicate the following features. First, spectral reflectance in red and near infrared increases with increasing the number of overlap leaves and narrowing the perpendicular space between leaves, but visible rays are not affected by these factors. Secondly, when the perpendicular space between leaves is wide, the spectral reflectance is affected by incident angle. Thirdly, the changes of spectral reflectance differ with leaf angle. These results lead to the conclusion that the relationship between those parameters is complex.

DOI： 10.2480/agrmet.52.567

Language：English   Publishing type：Research paper (scientific journal)  

The purpose of this study is to monitor land and water management using remote sensing and Geographical Information System (GIS). The Fourth Drainage Project, which is located in the center of Punjab Province of Pakistan, was selected as a research field. The Project was launched in 1983 to combat the twin menace of waterlogging and salinity; the depth of the water table in 77% of the area was 0-1.5m, and 43% of the land was saline. A newly introduced subsurface drainage system and a remodeled surface drainage system by the project have gradually reduced the waterlogging problem. The salinity problem, however, still remains. Analyzing Landsat-TM, GIS and ground truth data, following results were obtained. Waterlogging and salinity problems are mainly distributed along the drainage canals. The main reason is that the water table along the drainage canals is shallower due to the relatively low location. The Normalized Difference Vegetation Index (NDVI) tends to be lower along drainage canals and higher along the irrigation canals. It is mainly because of the unbalance of water distribution as a result of the locational disadvantage of downstream farmers. By contrast, an enterprise farm near the project does not show these locational unbalances but exhibits high NDVI values almost all over the farm, except for fallow. It is due to the fact that the water management there is demand-oriented, thus more flexible, and sufficient water is supplied.

DOI： 10.2480/agrmet.52.665

Language：English   Publishing type：Research paper (scientific journal)  

It is well known that soil water content at the surface of sand increases at night, which is dry in the daytime. The mechanism of this phenomenon, however has not quantitatively clarified because continuous measurement of nighttime soil water content is very difficult. Thus, in this study, the method to estimate nighttime surface soil water content was examined by using the meteorological and soil physical data measured at Tottori sand dune in 1995. Albedo of the infrared radiation and thermal conductivity of the sand surface, which are readily calculable, were selected as the parameters of the estimation equation. Albedoes can calculate from the surface temperatures of sand measured by thermocouple and radiation thermometer, and sky temperature measured by radiation thermometer. Thermal conductivities can calculate from the radiation balance, heat balance, and temperature gradient at soil surface. The results show that thermal conductivities would give satisfying estimations of surface soil water content of sand surface.

DOI： 10.2480/agrmet.53.185

Language：English   Publishing type：Research paper (scientific journal)  

The bulk transfer method combined with the heat balance equation of the surface requires the bulk transfer coefficient for sensible heat flux C_HU and the surface moisture availability β (evapotranspiration efficiency) to evaluate the surface temperature T_s, sensible heat flux H and latent heat flux lE, respectively. This paper examines relations between these coefficients and various factors (soil moisture content, solar radiation). Meteorological observations on a sorghum field in Tottori sand dune were carried out for 6-28 August, 1994. Significant results of the observations are the followings: 1) The value of bulk transfer coefficient varied with the atmospheric stability. 2) The value of β increased with increasing solar radiation, and tended to a constant value (β=0.35) when the solar radiation exceeded about 600 Wm^-2. 3) The value of β increased according to the soil moisture content. Observations of T_s, H and lE were compared with the simulations with the single source model (Kondo and Watanabe, 1992). This model simulates well the observed values of the daily mean of T_s, H and lE within an error of about±20 Wm^-2,±20 Wm^-2 and ±1.1°C, respectively.

DOI： 10.2480/agrmet.53.131

Language：English   Publishing type：Research paper (scientific journal)  

Chikugo model, which was originally the climatological model to estimate Net Primary Productivity (NPP) of natural vegetation including underground organs, was applied to estimate agricultural productivity in Inner Mongolia in China. The results show that the natural grass productivity and the agricultural crop (cereals, pulse crops and potato) productivity under poor irrigation activities are linearly correlated with NPP. Agricultural crop productivity under various irrigation ratios (irrigated area divided by cropping area) are not directly related with NPP. However, the rates of agricultural crop productivity to NPP are linearly correlated with irrigation ratios. Therefore, Chikugo model can be applicable to evaluate the potential productivity of both natural grassland and farmland, and offer an index of the proper agricultural development.

DOI： 10.2480/agrmet.51.21

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2480/agrmet.48.667

Language：Japanese   Book type：Scholarly book

Responsible for pages：これからの緑地環境，128-131   Language：Japanese   Book type：General book, introductory book for general audience

Responsible for pages：33-45   Language：Japanese   Book type：Scholarly book

Responsible for pages：2-25   Language：Japanese   Book type：General book, introductory book for general audience

Language：English   Book type：Scholarly book

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Responsible for pages：217-220、2012年2月24日   Language：Japanese   Book type：General book, introductory book for general audience

Language：English   Book type：Scholarly book

The Yellow River

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Environmental Biometeorology

Responsible for pages：pp.224-231   Book type：General book, introductory book for general audience

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Responsible for pages：pp.203-211   Language：Japanese   Book type：General book, introductory book for general audience

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Forest Field Sciences

Responsible for pages：pp.3-19   Book type：Scholarly book

Language：Japanese   Book type：Scholarly book

Environmental Biophysics 2nd Ed.

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Repository Public URL： http://hdl.handle.net/2324/1001175065

Responsible for pages：pp.240-251   Language：Japanese   Book type：Scholarly book

Responsible for pages：pp.18-47   Language：Japanese   Book type：Scholarly book

Regional Environmental Hydrology

Responsible for pages：pp.210-214   Language：Japanese   Book type：Scholarly book

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Venue：九州大学図書館（福岡市）   Country：Japan  

Event date： 2016.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学図書館（福岡市）   Country：Japan  

Event date： 2016.11

Language：English   Presentation type：Oral presentation (general)  

Venue：HOTEL INTERCITI, Taejon   Country：Korea, Republic of  

Event date： 2016.10

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Kangwon National University   Country：Korea, Republic of  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：日本大学生物資源科学部（神奈川県藤沢市）   Country：Japan  

Event date： 2016.3

Language：English   Presentation type：Oral presentation (general)  

Venue：Sendai International Center (Sendai, Miyagi)   Country：Japan  

Event date： 2016.1

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学図書館（福岡市）   Country：Japan  

Event date： 2015.12

Language：English   Presentation type：Oral presentation (general)  

Venue：San Francisco   Country：United States  

Event date： 2015.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Kelowna, British Columbia   Country：Canada  

Event date： 2015.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Kelowna, British Columbia   Country：Canada  

Event date： 2015.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Kelowna, British Columbia   Country：Canada  

Event date： 2015.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Kelowna, British Columbia   Country：Canada  

Event date： 2015.1

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学図書館（福岡市）   Country：Japan  

Event date： 2014.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Salt Lake City, Utah   Country：United States  

Event date： 2014.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：KITEN 宮崎グリーンスフィア壱番館コンベンションホール，宮崎市   Country：Japan  

Event date： 2014.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：KITEN 宮崎グリーンスフィア壱番館コンベンションホール，宮崎市   Country：Japan  

Event date： 2014.9

Language：English   Presentation type：Oral presentation (general)  

Venue：KITEN 宮崎グリーンスフィア壱番館コンベンションホール，宮崎市   Country：Japan  

Event date： 2014.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：KITEN 宮崎グリーンスフィア壱番館コンベンションホール，宮崎市   Country：Japan  

Event date： 2014.9

Language：English   Presentation type：Oral presentation (general)  

Venue：KITEN 宮崎グリーンスフィア壱番館コンベンションホール，宮崎市   Country：Japan  

Event date： 2014.4 - 2014.5

Language：English   Presentation type：Oral presentation (general)  

Venue：Viena   Country：Austria  

Event date： 2014.3

Language：English   Presentation type：Oral presentation (general)  

Venue：大宮ソニックシティ   Country：Japan  

Event date： 2014.3

Language：English   Presentation type：Oral presentation (general)  

Venue：大宮ソニックシティ   Country：Japan  

Event date： 2014.3

Language：English   Presentation type：Oral presentation (general)  

Venue：大宮ソニックシティ   Country：Japan  

Event date： 2014.3

Language：English   Presentation type：Oral presentation (general)  

Venue：大宮ソニックシティ   Country：Japan  

Event date： 2014.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：大宮ソニックシティ   Country：Japan  

Event date： 2014.3

Language：English   Presentation type：Oral presentation (general)  

Venue：大宮ソニックシティ   Country：Japan  

Event date： 2014.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：大宮ソニックシティ   Country：Japan  

Event date： 2014.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：大宮ソニックシティ   Country：Japan  

Event date： 2013.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学百年記念館（神戸市）   Country：Japan  

Event date： 2013.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学百年記念館（神戸市）   Country：Japan  

Event date： 2013.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学百年記念館（神戸市）   Country：Japan  

Event date： 2013.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学百年記念館（神戸市）   Country：Japan  

Event date： 2013.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学百年記念館（神戸市）   Country：Japan  

Event date： 2013.6

Language：English  

Venue：Ghent   Country：Belgium  

Event date： 2011.11

Presentation type：Oral presentation (general)  

Venue：GEカレッジホール，東京   Country：Japan  

Event date： 2011.11

Presentation type：Oral presentation (general)  

Venue：Kyushu University, Fukuoka   Country：Japan  

Event date： 2011.11

Presentation type：Oral presentation (general)  

Venue：Kyushu University, Fukuoka   Country：Japan  

Event date： 2011.3

Presentation type：Oral presentation (general)  

Venue：震災のため中止：静岡大学，静岡市   Country：Japan  

Event date： 2011.3

Presentation type：Oral presentation (general)  

Venue：震災のため中止：静岡大学，静岡市   Country：Japan  

Event date： 2011.3

Presentation type：Oral presentation (general)  

Venue：震災のため中止：静岡大学，静岡市   Country：Japan  

Event date： 2011.3

Presentation type：Oral presentation (general)  

Venue：震災のため中止：静岡大学，静岡市   Country：Japan  

Event date： 2011.3

Presentation type：Oral presentation (general)  

Venue：震災のため中止：静岡大学，静岡市   Country：Japan  

Event date： 2011.3

Presentation type：Oral presentation (general)  

Venue：震災のため中止：静岡大学，静岡市   Country：Japan  

Event date： 2011.3

Presentation type：Oral presentation (general)  

Venue：震災のため中止：静岡大学，静岡市   Country：Japan  

Event date： 2011.3

Presentation type：Oral presentation (general)  

Venue：震災のため中止：静岡大学，静岡市   Country：Japan  

Event date： 2011.3

Venue：北海道大学，札幌   Country：Japan  

Event date： 2011.3

Presentation type：Oral presentation (general)  

Venue：北海道大学，札幌   Country：Japan  

Event date： 2010.12

Presentation type：Oral presentation (general)  

Venue：Moscone Convention Center, San Francisco, California, USA   Country：United States  

Event date： 2010.12

Presentation type：Oral presentation (general)  

Venue：Moscone Convention Center, San Francisco, California, USA   Country：United States  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：北京   Country：China  

Event date： 2010.9

Presentation type：Oral presentation (general)  

Venue：Tongji University, Shanghai, 13 September 2010 (Oral)   Country：China  

Event date： 2010.9

Presentation type：Oral presentation (general)  

Venue：法政大学（東京都）   Country：Japan  

Event date： 2010.6

Presentation type：Oral presentation (general)  

Venue：Taipei   Country：Taiwan, Province of China  

Event date： 2010.6

Presentation type：Oral presentation (general)  

Venue：Taipei   Country：Taiwan, Province of China  

Event date： 2010.6

Presentation type：Oral presentation (general)  

Venue：Taipei   Country：Taiwan, Province of China  

Event date： 2010.4

Presentation type：Oral presentation (general)  

Venue：筑波大学（茨城県つくば市）   Country：Japan  

Event date： 2010.4

Presentation type：Oral presentation (general)  

Venue：筑波大学（茨城県つくば市）   Country：Japan  

Event date： 2010.3

Presentation type：Oral presentation (general)  

Venue：東京大学   Country：Japan  

Event date： 2010.3

Presentation type：Oral presentation (general)  

Venue：東京大学   Country：Japan  

Event date： 2010.3

Presentation type：Oral presentation (general)  

Venue：東京大学   Country：Japan  

Event date： 2009.8

Presentation type：Oral presentation (general)  

Venue：石川県文教会館（金沢市）   Country：Japan  

Event date： 2009.8

Presentation type：Oral presentation (general)  

Venue：石川県文教会館（金沢市）   Country：Japan  

Event date： 2009.3

Presentation type：Oral presentation (general)  

Venue：京都大学（京都市）   Country：Japan  

Event date： 2009.3

Presentation type：Oral presentation (general)  

Venue：京都大学（京都市）   Country：Japan  

Event date： 2009.3

Presentation type：Oral presentation (general)  

Venue：京都大学（京都市）   Country：Japan  

Event date： 2009.3

Presentation type：Oral presentation (general)  

Venue：京都大学（京都市）   Country：Japan  

Event date： 2009.3

Presentation type：Oral presentation (general)  

Venue：京都大学（京都市）   Country：Japan  

Event date： 2009.3

Presentation type：Oral presentation (general)  

Venue：京都大学（京都市）   Country：Japan  

Event date： 2009.3

Presentation type：Oral presentation (general)  

Venue：京都大学（京都市）   Country：Japan  

Event date： 2009.3

Presentation type：Oral presentation (general)  

Venue：岩手県立大学（盛岡市）   Country：Japan  

Event date： 2009.3

Presentation type：Oral presentation (general)  

Venue：岩手県立大学（盛岡市）   Country：Japan  

Event date： 2006.12

Presentation type：Oral presentation (general)  

Venue：京都大学百周年時計台記念館2階交際交流ホール   Country：Japan  

Language：Japanese  

Country：Japan  

Presentation type：Oral presentation (general)  

Venue：岡山大学（岡山市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：熊本県立大学（熊本市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：岩手大学（盛岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：岩手大学（盛岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：岩手大学（盛岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：岩手大学（盛岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：岩手大学（盛岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：岩手大学（盛岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京大学愛知演習林（瀬戸市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：札幌コンベンションセンター（札幌市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京大学（東京）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京大学（東京）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京大学（東京）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京大学（東京）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京大学（東京）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京大学（東京）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京大学（東京）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：北海道大学（札幌市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京農業大学(東京都）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京農業大学(東京都）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京農業大学(東京都）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：和歌山県民文化会館（和歌山市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：和歌山県民文化会館（和歌山市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：県民文化会館（鳥取市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：岡山大学（岡山市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：熊本大学（熊本市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：熊本大学（熊本市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：島根大学（松江市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：愛媛大学（松山市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：愛媛大学（松山市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：九州大学（福岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：九州大学（福岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：九州大学（福岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：九州大学（福岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：九州大学（福岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：九州大学（福岡市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：名古屋大学（名古屋市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：名古屋大学（名古屋市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：名古屋大学（名古屋市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：島根大学（松江市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：島根大学（松江市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京農工大学（府中市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京農工大学（府中市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京農工大学（府中市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京農工大学（府中市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：東京農工大学（府中市）   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：福岡国際会議場（福岡市）   Country：Japan  

Language：Japanese  

Country：Japan  

Language：Japanese  

Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：宇都宮大学   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：宇都宮大学   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：宇都宮大学   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：宇都宮大学   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：宇都宮大学   Country：Japan  

Language：English  

Venue：Fukuoka   Country：Japan  

Language：English  

Venue：Fukuoka   Country：Japan  

Language：English  

Venue：Fukuoka   Country：Japan